New Energy and Industrial Technology Development Organization (NEDO) and Bridgestone Corp developed a rubber whose energy loss and abrasion resistance are 40% less and 25% higher, respectively, than those of the rubber used for the tread of Bridgestone's "Ecopia" fuel-efficient tire for passenger vehicles.
In addition to NEDO, which is a Japan-based independent administrative institution, and Bridgestone, the research was jointly conducted by JSR Corp, the World Premier International Research Center Initiative-Advanced Institute for Materials Research (WPI-AIMR) of Tohoku University, the Institute for Materials Chemistry and Engineering of Kyushu University, the Nano Technology Research Institute (NRI) of Japan's National Institute of Advanced Industrial Science and Technology (AIST).
When a tire is rolling, the shape of its rubber keeps changing, resulting in energy loss. About 90% of the rolling resistance of a tire is accounted for by energy loss. Traditionally, the energy loss is reduced mainly by controlling the dispersion state of bulking agent. However, this method lowers performance including abrasion resistance.
As a result of the latest development, it became possible to independently control the form of polymer blend (in increments of 1,000nm), the dispersion of bulking agent (in increments of 100nm) and the cross-linked network (in increments of 10nm). The research group controls the form of the blend by optimizing marginal modified polymer, improving abrasion resistance.
To reduce loss, the group optimized the position of the bulking agent by using special equipment. Also, it uniformed the distribution of the cross-linked network by optimizing the vulcanization conditions to further reduce the loss.
As a result, the research group developed a rubber material that has a low energy loss and a high abrasion resistance. By using the evaluations, analyses and prediction approaches obtained through the development, Bridgestone aims to develop a tire whose rolling resistance is 20% less than that of the fuel-efficient tire that the company sells now.