Toray Industries, Inc. (Tokyo) and PTT Global Chemical PLC (PTTGC; Bangkok, Thailand) have established a first-of-a-kind series of manufacturing technologies for bio-based adipic acid (the main raw material of nylon 66) through the fermentation of bio-muconic acid using starch residues, ultimately producing 100% bio-based nylon 66 using it.
As there is a global demand to reduce greenhouse gas emissions and reduce dependence on fossil resources, the chemical industry is attracting attention to the effective use of renewable resources, such as biomass raw materials, that do not compete with food. Cassava pulp is a residue discharged in the process of producing starch from cassava, which is grown in large quantities for food applications, and is a raw material that can be expected to be stably supplied. By utilizing such unused resources, it is less likely to lead to new farmland expansion, which will lead to a reduction in the risk of indirect land use change (ILUC). To this end, the development of technology is also important to leverage unused resources converting to valued products.
Source: Toray
The following is an overview of the demonstration tests conducted by the two companies along a series of manufacturing processes in establishing this technology.
Saccharification. Toray has demonstrated the production of 5 dry-tons of glucose sugar per day using 66 tons of starch residue (cassava pulp) with approximately 85% moisture as raw materials, using an nergy-saving and high-quality saccharification technology using separation membranes.
Fermentation. PTTGC has proven that it can stably produce a fermented broth of bio-muconic acid with high efficiency from sugars made from the company’s proprietary strain. This showed the successful validation of technology from lab through to pilot scale fermenter (approx. 50 m³).
Refinement. High-purity bio-muconic acid has been refined from the fermentation broth using the unique technology developed by both companies. The high quality of refined bio-muconic acid enables it to be converted to bio-based adipic acid.
Chemical conversion. Toray has demonstrated bio-based adipic acid production from bio-muconic acid, ensuring the high purity quality required for nylon 66 polymerization.
Polymerization and fibrosis. Toray has demonstration the successful polymerization and fiber processing of nylon 66 on a lab scale using bio-based adipic acid and bio-based hexamethylenediamine (HMDA).
In the future, the companies will work to scale up and reduce costs in the production of bio-muconic acid and bio-based adipic acid, and Toray will continue to build a supply chain with the goal of starting sales of textile products using 100% bio-based nylon 66 by FY2028.