AIST Stories No2
10From AIST to the Innovative Worldwas welcomed by industry and currently, it has been widely introduced in fields such as thermal power stations, nuclear power stations, paper making plants, chemical plants, and petrochemical plants. Subsequently, new products have been developed almost on an annual basis; starting with the development of a hydrogen gas barrier composite material in 2008 and including a self-healing gas barrier film and a heat-resistant electrically-insulating film.Expanding applications, even in fuel cell vehicle hydrogen tanksThe water vapor and gas barrier properties, and superior heat resistance of Claist are highly sought after for many applications.One such application is the barrier material in hydrogen tanks fitted to fuel cell vehicles. Amid an advancing global transformation from a carbon society to a hydrogen society, the spread of fuel cell vehicles is forecast to accelerate, with their fuel being none other than hydrogen. Hydrogen molecules are the smallest among gases; they easily leak through the minutest of gaps. Further, leakages can potentially lead to explosions.The key requirements for fuel tanks used in fuel cell vehicles, which drive around with such a burnable fuel on Hugely successful in chemical plants as an alternative material to asbestosSince 2004, AIST has applied for numerous basic and applications patents based on this research as well as disseminating press releases about this heat-resistant barrier material based on clay film. Around 500 technical inquiries from Japanese and overseas parties have also been addressed and Ebina thereby came to realize the extent of related needs.In actual fact, a diversity of technology fields can utilize the high barrier properties of Claist. As previously mentioned, high-performance, high-durability sealants are indispensible in ensuring the safety of chemical plants.“For example, Teflon*4 used as a sealant softens at temperatures greater than 260°C and sealing properties are degraded. However, there are no such problems with Claist even at high temperatures of more than 300°C. Furthermore, traditional sealant sheets known as gaskets (employed at the joints between pipes) used asbestos*5, but its use has now been prohibited on account of adverse health effects. For this reason, development of an alternative material to asbestos was prioritized.”Use of asbestos, with its accompanying high durability and heat resistance, was no longer possible; the graphite used in its place was somewhat difficult to handle. In this situation, Claist, a material with good barrier properties and moreover easy to handle, was born. AIST and Japan Matex commenced joint development of an asbestos alternative gasket: in 2007, they completed a gasket with the highest performance among those utilized in Japan. This product ▲Clay synthesis. Clay synthesized in a pressure vessel is used to fabricate a transparent film.*4 Teflon: A type of fluororesin and trademark of U.S. company DuPont. The polymer exhibits excellent heat resistance, chemical resistance, flame retardance, and non-stick properties.*5 Asbestos: A fibrous mineral with excellent heat resistance, heat-retention properties, fire-retardance, sound-proofing, and wear resistance properties. Usage is currently prohibited on account of the high risk of lung cancer and mesothelioma among those exposed.