Using Cellulose Nanofiber to Reduce Auto Weight

Nanocellulose Forum, a trade show on technologies related to cellulose nanofiber (CNF), took place at EcoPro 2016, which ran from Dec 8 to 10, 2016, at Tokyo Big Sight.

CNF is a fibrous material that is made of cellulose (one of the main components of plants) and has a dimeter of three to several tens of nanometers. It is made by processing and untangling pulp derived from wood, etc.

At Nanocellulose Forum, CNF-based auto parts, bone prosthetic material, ballpoint pen, etc manufactured by businesses and research institutes were exhibited.

Kyoto University unveiled an engine cover formed by using CNF-added polyamide (PA, percentage by mass: 5%). When CNF is mixed with plastic as a reinforcing material, it becomes CNF-reinforced plastic, which has a light weight and a high strength. The engine cover was formed by using CNF-reinforced plastic and foaming it (expansion ratio: 300%).

The mass of the cover is as low as about 600g while the mass of a conventional engine cover made of glass fiber-reinforced PA (percentage by mass: 30%) is about 900g. In other words, the use of CNF reduced engine cover weight by about 30%.

Kyoto University developed “Kyoto Process,” which produces CNF-reinforced plastic while reducing the cost of CNF, and it has been developing CNF for auto parts. Moreover, it plans to examine how much fuel efficiency can be improved by applying CNF to auto parts by fiscal 202

High-value-added bone prosthetic material

Daio Paper Corp showcased an artificial bone prosthetic material made by using CNF for the first time. The company produces it by mixing CNF with calcium phosphate (main material) and performing drying, shape forming and sintering processes.

When the mixed CNF is burned out in the sintering process, many hole structures (open pores) are made from the surface to the inside.

“When body fluid easily soaks into the inside from holes on the surface, the bone prosthetic material is more easily integrated with the patient’s bone,” Daio Paper said. “Also, if medicine is put in the material in advance, it can be used for medical treatment.”

Conventionally, a porous material was made by adding foaming agent. Though this method can make holes inside the material (closed pores), it is difficult to make holes that run from the surface to the inside. Therefore, CNF, which is thin and long, was added so that such holes can be made.

The ratio of open pores of the new bone prosthetic material is 43-53% while that of the product using foaming agent is 30%. Daio Paper developed it in collaboration with Fukuyama (medical equipment manufacturer based in Chiba City) and Chiba Institute of Technology.

Ballpoint pen using CNF-containing ink

Mitsubishi Pencil Co Ltd showed a ballpoint pen whose ink contains CNF. A CNF solution has a property called “thixotropy,” with which an object becomes a sol(liquid) when a force is applied and a gel (solid) when no force is applied. The company developed a ballpoint pen that enables to smoothly write by adding CNF to ink

Jan 5, 2017
Kou Nonomura

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