The new bioplastic consortium project partners are: Hiroshima University, Nishikawa Rubber Co. Ltd., Western Hiroshima Prefecture Industrial Research Institute, G.P. Daikyo Corporation, Japan Steel Works Ltd., Kinki University School of Engineering, Nishikawa Kasei Co. Ltd., National Research Institute of Brewing, Yasuhara Chemical Co. Ltd., MANAC Incorporated and Mazda Motor Corporation. This is a consortium consisting of two universities, seven companies and two research institutes.

This newly-developed bioplastic is made of 88% corn and 12% petroleum. Mainly using corn-based polylactic acids, Nishikawa Rubber Co. Ltd, Hiroshima and Kinki Universities focused their efforts on developing a new nucleating agent for crystallization and a compatibilizer compound to raise the strength and heat resistance of the new plastic, increasing the potential applications in automobile manufacturing.

A nucleating agent acts as a catalyst and makes it easier to form crystals. Polylactic acid has properties which make for comparatively slower crystallization when compared to other plastics and this negatively impacts on production efficiency when molding bioplastics for car parts. Given this factor, it is necessary to carry out the crystallization earlier by means of a nucleating agent. When the molecular chain is arranged in a systematic way, the plastic’s strength is increased and its heat-resistant properties are improved.

The newly-developed bioplastic has three times the shock impact resistance along with 25% higher heat resistance when compared to contemporary bioplastics used for items such as electrical appliances.

In addition, it is made with a fermentation process that includes natural materials such as fermented starches and sugars which, compared with the process to make polypropylene, reduces energy use by 30%.

In contrast to current petroleum-based polypropylene plastics, the new bioplastic also has comparatively higher rigidity, resulting in thinner molds and fewer materials used. These attributes hold promise for better productivity in the mass production of vehicle parts, since parts manufacture frequently involves injection-molding equipment.

Mazda will continue its research and development in this area for the next several years, with any new advances to be employed in Mazda products.

Mazda and G.P. Daikyo Corporation are at the center of a world-class accumulation of automotive plastic module parts makers here in the Hiroshima area. Based on our rich tradition of sake brewing in this region, we’ve been accumulating fermentation biotechnology for a long time and Hiroshima University, Nishikawa Rubber Company and the Western Hiroshima Prefecture Industrial Research Institute—among other organizations—have an extensive history of research into the practical uses of biodegradable plastics than can be broken down by microorganisms.

In particular, great results have been achieved through joint international research into lactic acid copolymers. So it’s safe to say the Hiroshima area is fertile ground in terms of research achievements. Together with our regional partners over the next few years, Mazda intends to continue its bioplastics research for the purpose of utilizing any advances we achieve to make better products for our customers.

—Seita Kanai, senior managing executive officer in charge of Mazda’s R&D

Mazda will exhibit vehicle interior parts made with the newly-developed bioplastic in its booth at the Automotive Engineering Exposition at the Japan Society of Automotive Engineering (JASE) Annual Congress, to be held at the Pacifico Yokohama complex from May 24-26, 2006.