Bioplastics for Electronic Equipment

Tackling the development of biomass-based plastics -(Bioplastics) for electronic equipment-

High Performance Bioplastic with a High Plant Ratio by Using Non-edible Plant Resources: Plant Stems and Cashew Nut Shells (Cellulose Resin Bonded with Cardanol)

We have developed a first-of-its-kind durable new bioplastic that is produced from stable, non-edible plant resources. The bioplastic is created by bonding cellulose, a main component of plant stems, with cardanol, a primary component of cashew nut shells, which achieves a level of durability that is suitable for electronic equipment and boasts a high plant composition ratio of more than 70%.--> Aug.25.2010 Press Release

Polylactic acid (PLA), a representative of mass-produced bioplastics, which NEC uses in the PLA composites above mentioned , primarily uses starch made from feed grains (old crops) as a plant resource, and therefore, its usage does not cause to conflict food at present. However, the future possibility of food shortages has drawn attention to the importance of using non-edible plant resources to produce bioplastics.

Therefore, bioplastics produced from non-edible plant-based materials have been developed using such resources as cellulose and castor oil. Cellulose, the world’s most abundant non-edible plant resource is a main component of grass stems, crops and wood; the annual available amount is comparable to that of petroleum. Cellulose-based bioplastics have conventionally been utilized in such products as stationery, toys and household goods. However, these cellulose bioplastics require large amounts of petroleum-based additives such as plasticizers, which results in bioplastics with a low plant component ratio and poor durability, including insufficient heat resistance and water resistance. A polyamide resin derived from castor oil, a non-edible plant resource is also being used, however, there is an inadequate supply of this plant resource to expand its use and its characteristics are unsuitable for use in a variety of durable products, including electronics.

To resolve these issues, we have developed a new bioplastic by using cellulose as the main ingredient and cardanol as a modifier to react with cellulose (cellulose resin bonded with cardanol). Cardanol is an oil-like material extracted from cashew nut shells, which are often a discarded byproduct of the agricultural process, and represent a non-edible plant-based resource　with a stable supply. Cardanol has a unique molecular structure consisting of a flexible and hydrophobic component: liner hydrocarbon and a rigid component: phenol. Therefore, after enhancing its reactivity, chemically bonding the modified cardanol with cellulose (cellulose acetate) produces a durable bioplastic that is strong, heat resistant, water resistant and non-crystalline (short molding time compared to petroleum based plastics). Furthermore, packing an aromatic ring compound in the gaps of the molecular structure of the bioplastic increases the strength, etc. The use of cellulose and cardanol, both plant resources, as the plastic’s primary components produces a plastic that features a high plant component ratio of more than 70%.

Looking forward, we will continue with research and development towards mass production of this bioplastic and improving its suitability, including greater flame retardancy and high fluidity in molding, for a wide range of electronic equipment within the 2013 fiscal year.

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