Last updated on October 2nd, 2023 at 12:28 am
The first filament yarn was introduced through natural silk yarn derived from nature. And with the advancement of science gradually yarns like Bulletproof and Ballistic were introduced. In this article, we will know about Filament, Bulletproof and Ballistic Yarns.
Definition of Filament Yarn
Man first learned the silk worm’s filament yarn technique, which extrudes fibroin – a viscous proteinous liquid through its two spinnerets. No sooner do these filaments come in contact with atmospheric heat than they solidify into yarns.
Artificial yarns can either be (a) regenerated (Viscose, polynosic, acrylics, and acetate) or (b) synthesized from petroleum byproducts (poly fibres). Fibres forming molecules themselves are like a yarn – too long as compared to width. These molecules are capable of linking and creating a long-chained polymer.
As for chemicals, raw materials, and time of reactions and temperature used in manufacturing vary from lot to lot; these poly fibres exhibit different dye take-up from one lot to another and should never be mixed at any stage.
Definition of Lusture
Fibre and filaments are most lustrous when they remain parallel to the yarn axis. Twist reduces lusture. More the twist lesser the lusture. Poly fibres possess a natural synthetic sheen.
Lusture is a phenomenon of light reflection. The smoother the surface more the reflection. In twinkle nylon, light rays are made to enter one yarn face and remerge from the same face. This total internal reflection principle becomes possible because of a triangular, colorful cross-section of the nylon filament.
Yarn with a mixture of coarse and fine fibres will be hairier than all rough or all fine fibre yarn and diffuse light instead of reflecting it. Synthetics have a typical glitter which is not always a desirable attribute.
Bullet Proof, and Ballistic Yarns
Fabrics that can withstand and resist the impact of single or rapid small firepower are made with super-strong synthetic continuous filaments. The most popular among them, KEVLAR – 29, is used for making vests for army personnel.
Manufactured by Du Pont U.S.A in several types, Only Kevlar 29 – an Aromatic Polyamide (Aramide) is tough enough to absorb the force of a bullet and dissipate the heat and impact energy without cracking.
Properties of Bullet Proof Yarn
- Tenacity is superbly high – twice and more than polyester and nylon.
- Average molecular chain length (M) 20,000.
- Breaking strength 20 dynes/tex at 2% strain.
- Specific tensile strength 525 lb/in.
- Sp. Strength modulus doubles of glass and 20 times more than best steel.
- Chain length 108 µ (µ = 10-6).
- Tenacity 22 g/dtex.
Sometimes, the impact of powerful close-range bullets of Colt, Mauser or AK-47, do crack KV fabric. Then the next generation fibre P84 can be used. Its tensile strength is 33g/dtex against KV’s 22-or its strength is 1.5 times more. It is an aromatic Poly Cimide. In KV or P84 – molecular chains are highly oriented along fibre axis, as shown in fig. There is no amorphous region. Each chain is pressed side by side and held together by Van-der-walls forces. Hydrogen and co-valent bonds become armour when woven and shrunk to correct specifications, though such reflections are beyond the limits of this minor feature.
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