METALLIC FIBRE

1) The term metallic fibres, in its general sense, means simply a fibres that is made from metal. The generic term “metallic” was adopted by the U.S. Federal Trade Commission and is defined as: A manufactured fibre composed of metal, plastic-coated metal, metal-coated plastic, or a core completely covered by metal.

2) These metal filaments were made by beating soft metals and alloys, such as gold, silver, copper and bronze, into thin sheets, and then cutting the sheets into narrow ribbon-like filaments. The filaments were used entirely for decorative purposes, providing a glitter and sparkle that could not be achieved by other means.

3) As textile fibres, these metal filaments had inherent short comings which restricted their use. They were expensive to produce; they tended to be inflexible and stiff, and the ribbon-like cross-section provided cutting edges that made for a harsh, rough handle; they were troublesome to knit or weave, and they had only a limited resistance to abrasion. Apart from gold, the metals would tend to tarnish, the sparkle being dimmed with the passage of time.

METAL FIBRE PROPERTIES

A) Metal Fiber Fineness

1) Due to its history as a wire drawn product and its abnormally high specific gravity, metal fiber sizes are typically described in terms of their actual diameter in microns as opposed to their linear weight in denier.

2) As an illustration, a single human hair is 70 micron in diameter, and the current working range of bundle drawn stainless steel fibers is from 1- micron diameter to 100-micron diameter. Most textile applications utilize fibers in the range of 8 to 14 microns. As a way of comparison with polyester, a 12-micron metal fiber has the same diameter as a 1.4 denier polyester fibre.

B) Electrical Conductivity / Electro-Magnetic Shielding

1) Certainly, the most distinguishing property of metal fibers is its electrical conductivity.

2) When compared on a sq.cm basis, metal fibers can be classified as true conductors.

3) Carbon fibers and anti-static finishes, on the other hand, are electrically classified as Semi-conductors.

4) These differences can be significant in anti-static applications where atmospheric humidity is low and washing durability is an issue.

5) This high electrical conductivity also leads to good EMI shielding characteristics. Stainless steel fibers have long been utilized as an additive to plastic casings as a way to shield internal components from electromagnetic radiation.

6) As concerns around EMI shielding grow, these conductive plastic applications have expanded a variety of textile applications for metal fibers.

7) Garments, seals, gaskets and wall-coverings are all commercial application areas for shielding fabrics. There is even ongoing research into the possible therapeutic value of such fabrics for various medical treatments.

C ) Heat Resistance and Strength:

1) There exist many industrial environments that operate above the long-term working temperature of fiber glass and aramid fibers.

2) This is especially true in glass forming processes where temperatures can range from 450 to 6000 C.

3) In this particular application, there are other fibers that can withstand these temperatures from decomposition or melting standpoint, but they experience such a significant loss in strength or flexibility, that their resistance to mechanical