Currently, most plastic production from biomass either utilises the extracted oils, fat and sugar components as they are or breaks down the constituent sugar components into monosaccharides, which are then converted into monomers and polymerized to obtain plastics. In the former case, there is often competition for food, and in the latter case, the conversion process is economically and energy inefficient. Therefore, this study aims to develop a technology that enables cascade utilization of biomass according to its tissue structure and molecular weight. In other words, when unused biomass is converted by enzymes, we aim to develop a “biomass fractionation technology” in which, depending on the degree of enzymatic treatment, the parts that tend to remain as fiber and components that are chemically difficult to break down, are used as polysaccharides and oligosaccharides. The parts that are easily broken down are then used as monosaccharides.

Promotion of the Plastic Resource Recycling Law was promulgated in June 2021 and came into effect in April 2022. The Law has established a roadmap for the promotion of resource recycling initiatives for every aspect of the commercial flow of plastic materials/products – from product design to waste disposal, and beyond. In May 2024, The Act on Advancement of Recycling Businesses, etc. was passed and enacted by the Plenary Meeting of the House of Councilors. The Law expects manufacturers and distributors of plastic materials/products to take an initiative in utilizing recycled materials in their own materials/products. While there is a growing trend, mainly in Europe, to mandate the use of recycled materials in automobiles and other products, discussions are underway to formulate the Fifth Basic Plan for the Promotion of a Recycling-Oriented Society, which includes the two laws mentioned above. The plan will for the first time clearly state the transition to a circular economy and, together with the realization of carbon neutrality, is expected to set forth specific directions and numerical targets for every type of material with a broader view toward strengthening industrial competitiveness. Both targets are difficult to achieve by the manufacturers of plastic materials/products alone. This paper introduces examples of how Mitsubishi Chemical is making efforts to address the production of sustainable plastics in order to promote the use of recycled materials．

In recent years, plastic waste problems have become increasingly severe, making the development of plastic recycling technologies an urgent priority. While thermal and material recycling constitute the majority of plastic recycling technologies, chemical recycling is essential when considering carbon cycling. Chemical recycling is also expected to have significant potential from the perspective of reducing carbon dioxide emissions and more efficient energy consumption. Particularly crucial to this is the development of chemical recycling technologies for hydrocarbon-based plastics, which are the majority of plastics and include ones such as polyethylene, polypropylene, polyvinyl chloride, and styrene resins. Therefore, this paper provides an overview of the current state of chemical recycling for plastics as well as the research trends in hydrogenolysis technology for polyolefinic plastics using heterogeneous catalysts, which have attracted significant attention in recent years. Additionally, we discuss our recent research on solid catalysts for the hydrogenolysis of polyolefinic plastics.

The mass production, mass consumption, and mass disposal of plastics are exacerbating issues related to climate change and resource depletion. In 2015, global plastic production reached approximately 400 million tons per year, with waste amounting to about 300 million tons annually. In developed countries, the desire for "material wealth" continues to grow, while in emerging countries, population growth and economic development are expected to further expand plastic consumption activities and increase waste.

　Sumitomo Chemical aims to contribute to the realization of a sustainable society by developing various environmental impact reduction technologies, including reduction of CO₂ emissions, curbing fossil resources use, and promotion of resource circulation. Particularly for acrylic resin（ PMMA）, the company is focused on chemical recycling that leverages its depolymerization characteristics to obtain MMA monomers with high yields. In collaboration with The Japan Steel Works, Ltd., Sumitomo Chemical is developing a high-efficiency thermal decomposition process using a twin-screw extruder, aiming for early social implementation. This technology is expected to significantly reduce CO₂ emissions while maintaining the same quality as conventional PMMA. Furthermore, Sumitomo Chemical is promoting recycling through regional resource circulation projects with local governments and collaborative efforts with brand owners, advancing initiatives towards the realization of a sustainable society.

Although plastic is an indispensable material in our daily lives, the plastics problem and issues related to climate change are expected to make addressing environmental issues through plastics recycling and other measures even more crucial.

　Polystyrene is widely used for beverage bottles, food trays, and various other packaging containers. Some items such as fish boxes and foam food containers are mechanically recycled, which makes polystyrene considered to be one of the most recycled resins.

　Even so, most waste polystyrene in Japan is developed for single-use packaging and incinerated for energy recovery purposes. Circular recycling is desirable as a lifestyle system because it can lead to the reduction of greenhouse gas emissions. For these reasons, our company is also developing environmentally friendly, circular-recycling technologies. This paper introduces our general chemical recycling monomerization technology. It then goes on to discuss mechanical recycling, biomass naphtha-derived polystyrene, and plant-based additive polystyrene, which are all part of our efforts to develop new, environmentally friendly technologies.

In recent years, there have been efforts to address plastic pollution including marine litter, to improve recycling rates, and moreover to politically regulate the recycled content of plastics. Therefore, along with proper treatment of waste plastics, there is a need for a mindset that embraces circumstance-adapted resource circulation that makes it possible to effectively use waste plastics by taking advantage of region-specific conditions. In response to such social requirements, this article introduces the results of our research, including: (1) a top-down estimation of waste plastic generation amounts by municipalities based on material flow analyses for plastic consumption; (2) analysis of the supply potentials of recycled plastics through mechanical recycling based on the accuracy verification of optical sorting; (3) evaluation of scenarios for circumstance-adapted chemical recycling centered around an oil refinery; (4) surveys of the current situations of recycling collection of plastic products in municipalities across the country and waste composition of plastic products being collected in Sendai City.