C1-01 Development of environmental testing, diagnosis, and tracer technologies and digital analysis platform for industrial applications
Collaborating Organization
Mitsui Chemicals, Inc.
Research and Development Overview
This research and development project aimed to contribute to the application of recycled polypropylene (PP) derived from general consumer goods to automotive parts. It focused on understanding the physical properties of recycled materials, organizing applicable parts areas, and establishing material design and evaluation technologies. Specifically, the resin properties and injection molding properties of various recycled PPs were evaluated, and their applicability to parts was examined through comparison with Japan Automobile Manufacturers Association (JAMA) target values. Furthermore, a compound formulation containing 25% recycled material was prototyped and evaluated.
In addition, the mechanical property changes after thermal aging, light/weather resistance, and fatigue testing of PP composite materials were analyzed to understand the long-term durability of recycled materials and composites. Moreover, technologies for evaluating the interfacial interactions between glass fibers/fillers and resins were developed using SEM, dynamic viscoelasticity, AFM, STEM-EELS, AFM-IR, solid-state NMR, etc., to elucidate factors contributing to property degradation.
Through these studies, the construction of a material design and evaluation foundation necessary for the development of recycled PP for automotive applications was promoted in collaboration with Mitsui Chemicals, Prime Polymer, and Mitsui Chemicals Analysis Center.
Progress and Results
Towards the development of recycled PP for automotive applications, we advanced material evaluation, formulation studies, durability analysis, and interface evaluation technology development, and organized the technical challenges and promising conditions for component applications. Specifically, we organized the resin properties and molded properties of various PPs derived from general consumer goods and systematized the applicable automotive component areas for each type of recycled material. As a result, we confirmed cases where a compound containing 25% recycled material could meet the target values equivalent to composite reinforced PP (2), demonstrating its applicability to some components. On the other hand, for composite reinforced PP (1), it became clear that there were still unmet requirements in areas such as low-temperature impact resistance and tensile properties, and we organized the challenges for future formulation improvement.
Through thermal aging, light/weather resistance, and fatigue tests of PP composites, we found that while short-fiber types showed relatively small changes in physical properties, long-fiber and talc-based types were significantly affected by the decline in properties and interface strength due to thermal aging. Furthermore, through analysis using SEM observation, dynamic viscoelasticity, AFM, STEM-EELS, AFM-IR, and solid-state NMR, we established an analytical platform to evaluate the interfacial interactions between fibers/fillers and resins and obtained findings suggesting that a decrease in interfacial interactions in long-fiber reinforced materials is involved in the deterioration of physical properties. In addition, a correlation was confirmed between the rate of deterioration of physical properties at 400 hours of lightfastness and 2000 hours of weather resistance in recycled materials, indicating the possibility of primary evaluation using lightfastness tests. Based on the above, we have established a research foundation for verifying the effects of additives and expanding their application in the following years.