Kelheim Fibers, a leading manufacturer of viscose specialty fibers, is incorporating IR-reflecting particles into fibers. Different levels of these particles were integrated into the fiber’s core, thereby preserving the fiber’s inherent properties, rather than being added as a topical finish using additives based on titanium oxide or other metal-based compounds.
Visible light is reflected by 90 to 95 per cent, while in the near infrared range, a reflectance of up to 90 per cent is reached, depending on the wavelength spectrum. This proves a clear benefit in the reflectance of direct sunlight, where the fiber is capable of providing a cooling effect, for example, by protecting the human body from outside radiation.
At the same time, the fiber may also be used in warming applications, where the thermal radiation emitted from the body is reflected by these particles back to the body, reducing the cooling effect and keeping the person warm. In the mid IR-range an increase of reflectance of about 20 per cent of m-IR radiation was achieved in tests compared to normal viscose.
The fiber can be used for both textile and nonwoven processes, where the fabric can either protect against outside influences or reflect the IR-radiation back to the inside source.