News Releases / 2012

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  • May 2, 2012

    Rengo Group Develops Flexible Radiation Shielding Sheet

    Rengo Co., Ltd. (Head Office: Kita-ku, Osaka; President & CEO: Kiyoshi Otsubo) and its subsidiary Nihon Matai Co., Ltd. (Head Office: Taito-ku, Tokyo, President : Masao Fujita) have recently developed a radiation shielding sheet, which reduces radiation dosage by providing a shield against radiation (patent application filed).

    Following the accidental leakage of radioactive materials from the Fukushima Daiichi Nuclear Power Plant as a result of the Great East Japan Earthquake on March 11, 2011, there are still areas with high radiation levels in the air and temporary storage sites and other locations with waste that includes radioactive materials from the decontamination procedures. This has given rise to the urgent issue of how to provide protection against the radiation.

    Previously, hard, heavy metal sheets have been used to shield against radiation. By contrast, the recently developed radiation shielding sheet made with thermoplastic elastomers is a light weight and very flexible shielding material. It is expected to have a wide range of uses, such as to reduce radiation from entering rooms, and as covers for contaminated waste kept in temporary storage sites during decontamination.

    Nihon Matai is a Rengo Group company specializing in heavy duty packaging. As a pioneer in packaging for Japanese industries, Nihon Matai provides their products for various types of heavy powder and granular materials, ranging from kraft paper bags to heavy duty polyethylene bags and Flexible Intermediate Bulk Containers. In particular, the company is the leading manufacturer of Flexible Intermediate Bulk Containers in Japan and the Maicon brand container bag is the leading brand in the global market.

    The radiation shielding sheet was developed through collaboration between Rengo’s Central Laboratory, which has expertise in radiation gained from research on applications for the high-density zeolite containing fiber, Cellgaia,® * and Nihon Matai research laboratories, which have been developing packaging for heavy materials and various resin processing technologies over a number of years. A patent application has been filed based on repeated demonstration tests conducted in areas where there are still high levels of radiation in the air.

    Going forward, urgent and continued efforts are needed to protect against radiation. To help in ensuring safety and peace of mind, Rengo has applied its technology and know-how as a “General Packaging Industry,” accumulated over many years in packaging, to make a contribution to society in the area of radiation countermeasures.

    *Cellgaia® is a high-performance pulp developed by Rengo made by crystallizing zeolite inside cellulose fibers at high density.


    Radiation Shielding Sheet Product Outline

    Features •Previous radiation shielding products have been made mainly from sheets of metal such as lead, making them heavy and hard to handle, and there have been concerns about their effects on the human body. By contrast, this product is comprised of soft thermoplastic elastomers* integrated with an inorganic substance that shields against radiation. Outstanding features are its flexibility and ease of handling.
    •The raw materials used in this product have been proven to be safe and have no effect on the human body.

    * Thermoplastic elastomer is a high-polymer material that possesses the properties of both plastic and rubber.
    Appearance 放射線遮蔽シート
    Specifications Thickness: 1mm–2mm; width: 500mm–2,000mm
    Sheets can be cut to the required size to suit the purpose of use.
    The radiation shielding rate can be increased by piling the sheets.  
    Examples of Radiation
    Shielding Rates
    Thickness of radiation shielding sheet Radiation
    shielding rate
    20mm Approx. 50%
    1mm Approx. 3%
    (The above values vary with different measuring conditions)
    Uses •Building materials for floors, walls, etc.
    •Curtains, carpets and other fittings for living spaces
    •Covers for temporary storage sites and other locations during decontamination Examples of use: As cover sheets for contaminated soil and other materials accumulated in Flexible Intermediate Bulk Containers and large sandbags, and as cover sheets for storage boxes during household decontamination
    •Cover sheets for removed vegetation and gutters