Denso Corporation announced that it is using bio-polycarbonate (PC) made from starch and urethane resin extracted from castor oil in some of its products. Denso says it has been conducting research and development on plant-derived plastic materials, which are based on plant molecular structures, in order to reduce impacts on the environment.
Starch-derived bio-PCs have higher surface hardness, better optical characteristics, and superior hydrolytic stability than conventional petroleum-derived PCs. Moreover, they refract less light, exhibit better colour-forming properties, and thus do not need to be painted before being used. Denso ‘s starch-derived bio-PC, which provides high hardness, yet can be shaped into complex designs, is being used to make plastic bezels for Toyota Motor Corporation’s genuine car navigation systems.
Castor oil, a vegetable oil extracted from castor beans, is used as a material in paints, waxes, and other products. Denso has developed a highly heat-resistant urethane resin based on the molecular structure of castor oil and used it as a protector for connectors in automotive exhaust gas sensors.
Automotive exhaust gas sensors, which measure the concentration of specific gases present in vehicle exhaust gases, must have high heat resistance. Therefore, the resins used in sensor control units have traditionally been expensive silicone-type resins. Denso ‘s newly developed urethane resin costs less than silicone resins and can withstand up to 150 °C, while significantly reducing the amount of gases produced when being melted and formed into shapes. This is the first such resin of its kind in the world.
Non-fossil plant-derived plastics are gaining increasing attention because they are inexhaustible resources and do not increase the total amount of CO2 in the atmosphere when thermally recycled. Therefore, Denso has been working on their development for some time. In 2009, Denso and DuPont jointly developed and commercialized a radiator tank made from a material extracted from castor oil and have been increasing the number of vehicle models that use the product.
In 2016, Denso established Denso ECO Vision2025, an action plan to help build a sustainable community and society toward 2050. Denso will continue to develop plant-derived plastics and increase the number of products made from these materials, and thus reduce the use of limited oil resources while decreasing CO2 emissions at all stages of the life cycle of products and curbing global warming.