Teijin Develops Radiation Shielding Aramid Fabric

TOKYO — April 24, 2013 — Teijin Limited <http://www.teijin.com/> announced today its
development of aramid fiber fabric that protects users against X-ray and gamma-ray radiation. The
company from May will provide samples to selected customers for applications such as protective
clothing and sheet materials used around high levels of radiation, including the medical field,
reconstruction activities in disaster-hit northeastern Japan and radiation testing.

The newly developed product, radiation shielding Technora fabric, is produced by blending
radiation-shielding tungsten particles with Technora high-strength para-aramid fiber that is
produced and sold by Teijin. 

The new product offers the following key features:

  • Due to the superior strength and modulus of para-aramid fiber, the product is stronger than
    polyester and other general-purpose fibers despite containing high concentrations tungsten, a
    high-density metal that tends to impair the fiber’s mechanical properties.
  • The level of radiation shielding corresponds to the amount of tungsten blended into the aramid
  • Fabric products offer excellent flexibility and workability for use in way not possible with
    lead plates or concrete.

In addition, tungsten-blended Technora fabric exceeds the already high levels of flame
retardancy and cutting resistance exhibited by the regular Technora aramid fiber. As such, Teijin
expects its new fabric to be used in materials and protective clothing for people handling
high-temperature objects and/or sharp-edged rubble, tools and so on.

While it is generally difficult to produce filament yarn by blending a high-density metal
with fiber, Teijin has overcome this challenge by leveraging its spinning know-how and the inherent
properties of Technora. The uniform blending of tungsten and fibers is achieved with Teijin’s
well-established polymer and spinning technologies. 

Teijin’s high-strength para-aramid fibers Twaron and Technora and meta-aramid fiber
Teijinconex, which offers superior long-term heat resistance and flame retardancy, are available
for a wide range of solutions where enhanced protection is required, such as law enforcement,
firefighting and manufacturing. In Japan, where the Great East Japan Earthquake of 2011 has raised
concerns about radiation in the region due to damaged nuclear reactors, Teijin believes that its
new aramid fabric will provide solutions that help to ensure the safety of workers involved in

Lead and lead-containing materials are typically used to shield against radiation because
lead is comparatively inexpensive and exhibits excellent shielding. However, due to concerns about
the environmental impact of lead, movements are underway to regulate its global use. Tungsten is
now being used as an alternative for radiation shielding because it has relatively little impact on
the human body or the environment.

Tungsten for radiation shielding is available in the form of fiber and sheet, and in hybrid
materials such as resin or rubber blended with tungsten. It has been difficult to produce a
tungsten hybrid in the form of fiber, however, due to problems with blending fiber with a
high-density metal like tungsten. In addition, high-density metal blended in a high concentration
with fiber using conventional methods tends to lose its strength and modulus.

Posted on April 30, 2013

Source: Teijin Ltd.