Denso’s new plant-based plastics includes bio-polycarbonate (PC) made from starch and urethane resin extracted from castor oil. Denso’s starch-derived bio-PC, which the company says provides high hardness yet can be shaped into complex designs, is being used to make plastic bezels for Toyota’s navigation systems.
Denso says its goal in developing plant-derived plastics is to reduce its environmental impacts. The bio-materials also perform better, according to the company.
Starch-derived bio-PCs have higher surface hardness, better optical characteristics, and superior hydrolytic stability than conventional petroleum-derived PCs. They also refract less light, exhibit better color-forming properties, and thus do not need to be painted before being used, the company says.
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. Because of this, 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 degrees C, while significantly reducing the amount of gases produced when being melted and formed into shapes, the company says, adding that this is the first such resin of its kind in the world.
Denso has been working to develop pant-based plastics, which are renewable and emit less CO2 during production than their traditional petroleum-based counterparts, for several years.
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.
Last year the company launched Denso Eco Vision 2025, its action plan to help build a sustainable community and society. The company says it will continue to develop plant-derived plastics and increase the number of products made from these materials as part of its ongoing efforts to decrease CO2 emissions at all stages of the life cycle of products and curb global warming.
Denso’s announcement follows a flurry of recent developments in plant-based plastics and other efforts to make plastics more environmentally sustainable.
Earlier this month the world’s two largest bottled water companies, Danone and Nestlé Waters, teamed up with a California startup to develop and launch at commercial scale a PET plastic bottle made from 100 percent bio-based material.
Last summer Toyota Tsusho, the Toyota Group’s trading arm, invested an undisclosed amount in sustainable technology company Anellotech, which is working to make 100 percent bio-based PET plastic.
And in 2015, Coca-Cola and Virent produced the world’s first PET plastic bottle made entirely from plant materials — but at demonstration scale. Coca-Cola has been producing partially bio-based PlantBottle since 2009, a product comprised of 30 percent plant materials.
The market for bio-based PET is projected to reach $13 billion by 2023, according to a market research report.