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Industry-academia consortium starts production of new modified lignin

2021.09.13

A consortium consisting of seven organizations, including LignoMateria and the Forestry and Forest Products Research Institute (FFPRI; Director Toru Asano), completed the setup of a demonstration plant in Hitachi-Ota city, Ibaraki Prefecture, on June 30 to manufacture a new material named "modified lignin" derived from Japanese cedar. Trial production will start at the their first plant to demonstrate the stable production of modified lignin.

Modified lignin is a new wood-derived material developed by the FFPRI and is expected to find wide industrial use owing to its heat resistance and environmental compatibility, characteristics that cannot be achieved with petrochemical products. Lignin, which is present in a relatively large amount (approximately 20 to 30%) in trees, is a general term for macromolecules with a benzene ring in the cell wall of plants and contributes to the suppleness of wood. Lignin has attracted attention as a candidate material owing to its high performance. One issue, however, is that its properties differ depending on the plant species and can be easily altered. Without treatment, its properties vary widely, making it difficult to prepare a highly functional industrial material.

Research at the FFPRI is ongoing to expand the applications of lignin and address the issue of the variation in properties, using the relatively uniform lignin from a Japanese tree, the Japanese cedar. The FFPRI also established a new manufacturing technology that enables reformation at the same time as extraction. Through this new technology modified lignin was successfully developed.

Since then, technological development has been promoted using modified lignin as a material for various advanced applications. Fiber-reinforced plastics (FRPs) using modified lignin as a resin have been developed. These materials have been considered for use in the exterior of automobiles and as woofer materials in high-resolution speakers. Manufacturing technologies for circuit boards using modified lignin and resin printing have also been developed.

Separately, supply technology was being developed at the bench plant installed at the FFPRI Center for Advanced Materials. However, the transition to pilot plant testing for industrialization was a challenge. Another issue was that the sample supply was insufficient.

To solve these issues a consortium comprising of LignoMateria, FFPRI, Tokyo University of Technology, MANAC, L & Cozy Co., Miyanosato Biomass LLP, and Neomateria was formed, and a demonstration plant for production was constructed as part of a subsidized project of the Forestry Agency. It was decided that the location should be close to existing forestry and timber industries, where wood resources are concentrated. Therefore, the plant was built adjacent to the Miyanosato Woody Biomass Power Generation Plant (inside the Miyanosato Industrial Park in Ibaraki Prefecture) operated by Hitachi Zosen Corporation. The use of waste heat from power plants is also being considered as a potential future development.

The demonstration plant system utilizes the results of the research obtained at the FFPRI bench plant related to efficiency improvements. The main process is an acid decomposition reaction in polyethylene glycol (PEG) under atmospheric pressure and a safe reactor system that does not use a pressure reaction vessel has been adopted.

Crushed Japanese cedar wood is introduced into the reactor together with PEG and a small amount of sulfuric acid catalyst and is decomposed by acid solvolysis by heating to 140 °C with stirring. A dilute alkaline aqueous solution is added to this mixture. Subsequently, a lignin decomposition product (modified lignin) bonded to PEG in a dissolved state in the alkaline aqueous solution is obtained. Modified lignin can be obtained as a paste-like solid by precipitating and filtering owing to its insolubility in the acid. After drying, the material is ready for use. The annual production capacity of the plant is 100 tons. PEG can be recovered from the remaining aqueous solution and can be reused. The pulp, which is a by-product, can be used as a cellulose fiber material.

Improvements in the product development process is anticipated through continuous operation tests and providing samples to companies operating in the industry.

This article has been translated by JST with permission from The Science News Ltd.(https://sci-news.co.jp/). Unauthorized reproduction of the article and photographs is prohibited.

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