Japanese chemical companies Asahi Kasei and Microwave Chemical launched a joint demonstration project in April 2023 in order to commercialize a chemical recycling method for polyamide 661 (PA66, often known as nylon 66).

The method is predicted to provide a high yield with little energy usage by employing microwaves to depolymerize2 PA66 and extract the monomers hexamethylenediamine (HMD) and adipic acid (ADA) directly. The resultant monomers can then be utilized to create fresh PA66. Depolymerized PA66 manufacturing waste and post-use trash for airbags and automotive components are used in the presentation.

Currently, Asahi Kasei produces HMD and ADA derived from fossil fuels as intermediates to create Leona™ PA663, an engineering plastic with exceptional heat resistance and rigidity. The demand for PA66, which is used in a variety of items like plastic parts for automobiles and electronics as well as yarn for airbag fabric, is predicted to rise globally.

In order to reduce greenhouse gas (GHG) emissions from chemical goods made from fossil fuels, industrial processes are receiving more attention as the world moves toward carbon neutrality. Using microwaves, which can directly and selectively heat target compounds with great energy efficiency, Microwave Chemical is pushing technological and commercial development to attain carbon neutrality in the industrial sector. Microwave Chemical is developing its proprietary PlaWave™ technology platform for decomposing plastic using microwaves.

The two businesses are working to commercialize a PA66 manufacturing process that emits fewer greenhouse gases than the standard manufacturing process by combining Asahi Kasei's more than 50 years of experience manufacturing HMD and ADA with Microwave Chemical's successes in industrializing microwave technology.

The high-yield depolymerization of PA66 utilizing microwaves, as well as the general idea of the separation and purification procedure after depolymerization, have been proven by laboratory-scale research that got underway in fiscal 2021. By the end of the fiscal year 2023, bench-scale equipment will now be put together at Microwave Chemical's Osaka factory. The equipment will then be used in a small-scale demonstration trial in the following fiscal year 2024 to gather preliminary process information for commercialization.

The PlaWave™ technology platform from Microwave Chemical can depolymerize PA66 with minimum energy and produce high yields of HMD and ADA monomers. The production of PA66 using HMD and ADA obtained through depolymerization with this technology is anticipated to emit fewer greenhouse gases than the production of PA66 using conventional methods. Additional GHG emission reductions may be made by using renewable energy sources to power microwave generators.

This demonstration project seeks to enable resource rotation of PA66 for further GHG emission reduction by confirming the process from depolymerization to separation and purification in an integrated manner.

Following a thorough analysis, a choice regarding the likelihood of commercialization will be made by fiscal 2025 based on the outcomes of the small-scale demonstration trial. Together with stakeholders in the PA66 value chain, the development of a business model that incorporates the entire value chain in the chemical recycling of PA66 will advance at the same time as the small-scale demonstration trial.

Through studies of the practical application of material recycling and chemical recycling as well as trials for the commercialization of PA66 made using intermediates derived from biomass, Asahi Kasei seeks to be a global partner for its PA66 customers by offering the best solutions for their carbon neutrality initiatives.

In order to achieve the practical application of the chemical recycling of polymethyl methacrylate (PMMA, also known as acrylic resin), automotive shredder residue (ASR), plastic containers and packaging, flexible polyurethane foam, etc., Microwave Chemical is working to increase the scale of equipment and to make PlaWaveTM more generally applicable.