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Through a joint project, the University of Fukui (Bunkyo Campus: Fukui City, Fukui Prefecture; President: Masaru Fukuda; hereinafter "University of Fukui") and Kuraray Co., Ltd. (Headquarters: Chiyoda-ku, Tokyo; President: Fumio Ito; hereinafter "Kuraray") have applied advanced fiber-processing technology—specifically, electron beam-induced graft polymerization—to successfully develop a special nonwoven fabric that selectively absorbs and separates metal ions. Building on this success, the University of Fukui and Kuraray are continuing to work together.

Following this achievement, the two parties entered began setting up a metal ion collection business that they hope to quickly launch as a Japan-based industry-university joint project. The two will work together to ensure appropriate materials collaboration for the electron beam-induced graft polymerization.

Having completed what had begun in 2010 as preliminary experiments aimed at facilitating this initiative, in July 2011 Kuraray and the University of Fukui entered into a full-scale joint study and applied for a joint patent.

The new technology will be introduced at booth E-03 by KURARAYKURAFLEX (a wholly owned Kuraray subsidiary) at "nanotech2012," which will be held at Tokyo Big Sight from February 15, 2012.

Background of the Development

• (1) The Hori Office (Professor Teruo Hori) of the Fiber Amenity Engineering Course, Graduate School of Engineering, University of Fukui, was studying the application of advanced fiber-processing technology with the aim of improving rare metal collection, a technology for which there is a pressing need.
• (2) During the course of study, the Hori Office discovered that Kuraray's FELIBENDY nonwoven fabric was particularly appropriate for use in this study, because it is made from fibers with a porous structure developed by applying steam heat. The Hori Office thus entered into joint technological development.

Overview of the New Technology

• (1) Applying an advanced processing technology called electron beam-induced graft polymerization to fibers enables the fibers to selectively absorb and collect metal ions, including those of rare metals, from solution.
• (2) The use of FELIBENDY, a nonwoven fabric made from the copolymer EVAL (ethylene vinyl alcohol polymer resin), which reacts readily to electron beam-induced graft polymerization, a process that increases the fabric surface area that comes in contact with the solution, allowed the realization of high-speed processing.

FELIBENDY and EVAL are registered trademarks of Kuraray.

Reference

Overview of the Metal Ions Collection System

Once activated through irradiation using an electron beam, the fibers have a structure that more easily absorbs metal ions. This is caused by the formation of absorption groups (functional groups) through graft polymerization, a unique effect of the process. Following this treatment, when the fibers are immersed in either sea water or industrial wastewater, they are effective in collecting metal ions. Then Ph adjustment separates the metal ions.
Using graft polymerization, the University of Fukui and Kuraray succeeded in developing a large variety of absorption groups (functional groups) for the selective collection and separation of metal ions.

Electron Beam-Induced Polymerization:

The result of irradiating highly polymerized compounds (such as fiber and film) with an electron beam to produce radicals. These radicals include monomers (highly responsive small compounds) that together form highly reactive functional groups that in chain reactions develop polymer-type molecules. The resulting compound contains molecules that look as if new molecules have been "grafted" on to preexisting polymer-type molecules.

Reasons FELIBENDY Nonwoven Fabric Was Selected

• FELIBENDY employs SOPHISTA (trademark registered by Kuraray), a core-sheath construction-type fiber, specifically, an EVAL sheath and a polyester core.
• Along with an intricate structure boasting numerous surfaces and evenly distributed porosity, the thickness and density of SOPHISTA’s fibers are easily modified.
• SOPHISTA offers superior advantages with regard to its fiber structure, which maximizes the fiber surface area that comes into contact with solution, and the smooth flow of solution through the nonwoven fabric facilitated by EVAL's hydrophilic property.
• Studies have revealed that EVAL with hydrophilic groups responds well to electron beam-induced graft polymerization. This led to the discovery that SOPHISTA fiber made from EVAL is also very effective at metal collection.

About FELIBENDY

The world's first nonwoven fabric made using steam jet technology. Utilizing Kuraray's proprietary SOPHISTA as a raw material, the Company applies unique production conditions to produce a wide range of FELIBENDY nonwoven fabrics.
Nonwoven fabrics made from high-temperature, high-pressure processed SOPHISTA can be further processed to manufacture thick board with a number of functions, including air permeability, sound absorbency, shock absorption and insulation.
Kuraray is responsible for development and KURARAYKURAFLEX the production and sale of FELIBENDY.

About EVAL (ethylene vinyl alcohol polymer resin)

EVAL was developed by Kuraray as the world's first copolymer EVOH (ethylene vinyl alcohol polymer resin) in 1972. Its structure consists of a number of hydroxyl groups hanging from a chain of carbon hydrate (CH₂). Owing to its gas impermeability, EVAL is used as a barrier material for food packaging materials and plastic gas tanks.

University of Fukui

Kuraray Co., Ltd.

KURARAYKURAFLEX CO., LTD.

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