Fibers which do not logically “fit” under other classifications are 1isted–novaloid, carbon, poly-phenylene-dibenzimidazole and polyimide fibers. These fibers were developed for specific industrial applications and do not find wide use in consumer goods.
Novaloid is the designation assigned by the FTC for a class of flame retardant fibers made from crosslinked phenol-formaldehyde polymer. The fibers of this class in U.S. production are called Kynol and are manufactured by American Kynol, Inc. The fiber is golden yellow in color and possesses good physical and chemical properties.
Novaloids are characteristically used in flame retardant protective clothing and in apparel and home furnishings applications where low fiber flammability is desired.
Carbon or graphite fibers have been developed recently for use in industrial and aerospace applications. The carbon fibers are prepared from rayon, acrylic, or pitch fibers by controlled oxidation under tension in a limited oxygen atmosphere at 300°-400°C.
Carbon fibers are extensively used in reinforcing fibers for resins and plastics in high-performance fiber-polymer composites and are marketed as Celion, Hi-Tex, and Thornel.
PBI was developed by the U.S. Air Force and Celanese as a flame retardant fiber for use in aerospace applications. The fiber is spun from dimethylacetamide followed by derivatization with sulfuric acid to form a golden fiber.
In recent years, it has shown potential as a replacement for asbestos, as a flue gas fi1ter material, and as an apparel fabric in specialized applications.
An aromatic polyimide has been introduced by Upjohn Company for use in flame retardant, high-temperature applications. The fiber is spun from the polymer by wet or dry processing techniques using a polar organic solvent such as-dimethylformamide.
Distinguishing with other Fibers
Ramie and linen which are called vegetable fibers are actually the skin (inner bark or bast) of a bush height plant. Ramie is from ramie plants, and linen is from flax plants. Therefore, theoretically, the fiber length can be as long as the length of the stem, but for making yarn, we usually make it into about 4” to 7 “ for spinning. Wool, Lamb’s wool and Angora rabbit hair are all hairs of animal’s .The length of these hair ranges from 3” to 8” proper for spinning into yarn.
Other than cotton vegetable fibers and wool, everything else) polyester, nylon, acrylic, acetate, and rayon etc) is the synthetic fiber of continuous or indefinite length.However, in order to make spun yarn, we cut the fiber into 5” to 8” length for spinning. Spun yarn is sometimes made in 2ply or 3ply. The following is how we call them:
- 20/2 means 20 count 2-ply
- 20/3 means 20 count 32-ply
- 10/2 means 10 count 2-ply
- 60/4 means 60 count 4-ply