Plastic is a unique material with a lot of benefits making it a highly valuable material for many functions and applications. While plastics can provide environmental benefits such as in maintaining food quality and safety and reducing food waste, plastic waste in the environment has become a global challenge. Now more than ever a paradigm shift from a linear to a circular economy is necessary. In this perspective innovative recycling method play an important role to find solutions. Accordingly, this report provides an analysis of the innovative activities in the recycling of plastic waste by performing a review of the patent activity in the field of polymer recycling.
The analysis of the patent landscape shows an increase of research related to recycling of plastics in recent years. At its peak in 2018, the research in recycling of polymers was about 12% of the research related to these polymers. Research is conducted by players across the value chain with Japanese applicants dominating among the companies filing patents on recycling and Chinese institutes showing most of the activity among academics in recent years. However, patent value analysis shows that patents having a high patent score and/or high amount of citations are generally from European and US companies which is indicative of the importance of the research conducted by European and US companies. Also, early patents with a high number of forward citations and/or a high patent score are from Western companies.
The highest amount of patents relates to recycling of polyester followed by polyurethanes. Alcoholysis and in particular glycolysis are the most often disclosed methods of recycling for these polymers. Polyolefin recycling is much less dealt with in the patent literature on recycling and they are often recycled using pyrolysis aiming to recycle energy and use as fuel. Hydrolysis is also mentioned in connection with the cleavage of thermoset olefin resins. Finally, dissolving or extracting of polymers in recycling is used to purify polymers, for example polyolefins and to selectively dissolve polymers in a blend of different polymers. Fibers in polymer composites may be recycled by depolymerization of the polymers in the polymer matrix.