Nanotect® – a strong, ductile composite coating made from carbon nanotubes

Description of products and technology

Created from a compound of steel and carbon nanotubes (CNTs), Nanotect® is a composite coating for metals providing powerful corrosion resistance for semi-permanent structures. It was developed for long use even in chemically and mechanically harsh conditions.  

The basic features required in a coating are long-term rust protection for steel, as well as hardness, ductility and sliding properties. In most coatings, there is a trade-off in these features, so that achieving a high-performing material in all areas is difficult to achieve. To overcome this problem, Takenaka developed a revolutionary grafting technology to produce Nanotect®, a truly unique material.

The research into CNT grafting was originally an example of surface-initiated graft polymerization developed by Dr. Fukuda, a professor emeritus of Kyoto University. With cooperation from Dr. Fukuda, Takenaka investigated a wider range of industrial applications for end grafting, and developed a new technology.

By nature, CNTs have an extremely low dispersion rate in solvents and polymer solutions; however, with the right combination of grafting polymers, grafting solvents and resin polymers, the dispersion can be greatly improved. Perfected with such techniques, Takenaka’s Nanotect® product is a new, semi-permanent material that is chemically and mechanically stable.  Technological advances achieved with Nanotect® include:

1. Uniform dispersion of grafted CNTs in coating solutions up to the high concentration of 10 weight%.
2. Dramatic improvements in ductility and strength through the higher concentration and uniform dispersion of grafted CNTs, as well as film hardness and abrasion resistance improvements of 1000% over conventional coatings.
3. Advanced rust protection proved in a 3000-hour salt spray test.
4. With the adoption of electrostatic coating technology, a coating efficiency triple that of conventional methods, boosting company production efficiency.

Product and technology specifications, recommended uses

Takenaka is currently developing new businesses with their Nanotect® product for nonscrew applications in extreme-environment markets. Aiming for growth for CNT composites in the coating market, Takenaka is working on applications for extreme environments such as deep-seabed drilling and deep-water survey ships, and in the environmental industry, which requires safety approvals such as for water supply systems.  

This technology is overturning the conventional concepts of organic films. With research into leading-edge materials for aircraft, high-speed rail and other advanced applications, Takenaka is forging ahead into new industrial fields using high-level films and sealing mechanisms to withstand even harsh environments.