NEC Corporation and UNITIKA LTD. will develop a bioplastic reinforced with kenaf fiber, which is expected to contribute greatly to environmental measures for mobile phones.

Kenaf is member of the hibiscus family (Hibiscus cannabinus L), and is related to cotton and okra. Kenaf grows quickly, rising to heights of 12-14 feet in as little as 4 to 5 months. It has a preeminent carbon fixation effect (1.5t of CO2 in the air is absorbed per 1t of kenaf).

NTT DoCoMo is already using this new material in the entire casing of its new FOMAâ„¢ N701iECO mobile phone, which it launched on the Japanese market on March 10, 2006. N701iECO is depicted below.

Biomass-based bioplastics, such as polylactic acid (PLA) that is made of corn, have been drawing attention in recent years as new materials to replace conventional petroleum-based plastics. However, application of regular PLA to electronic devices is difficult as it has insufficient heat resistance and strength.

NEC succeeded in improving the heat resistance and strength of PLA by adding kenaf fiber to it. Together with UNITIKA, it realized the durability of the new material by applying it to the components of a PC. More recent research carried out by both companies involved the further improvement of the characteristics of the kenaf fiber-reinforced PLA in order to allow its application to mobile phones. Its moisture resistance was improved by UNITIKA, using “TERRAMAC”, their commecialized PLA.

Fall impact durability was increased by adding a biomass-based flexibilizer and a reinforcing filler that NEC developed for this resin. In addition, moldability was further advanced by using original additives that were jointly developed by NEC and UNITIKA.

The newly developed bioplastic achieves the highest biomass ingredient ratio out of all bioplastics that are currently being used in electronic devices, with a ratio of approximately 90%. It simultaneously realizes a high level of fall impact durability, moldability and heat resistance, which are all desired features for mobile phone casing. Heat resistance was dramatically improved by adding kenaf fiber as a reinforcing agent to the polylactic acid, a typical bioplastic material. In addition, by adding a biomass-based flexibilizer and reinforcing filler, which have special compositions, the fall impact durability and strength characteristics have been improved.

NEC and UNITIKA will continue to advance application of the bioplastic to electronic devices toward the further reduction of environmental load.