Performance and Application of Nylon Filament
1. Performance
The softening point of PA 6 fiber is 180 ℃ and the melting point is 215-220 ℃, In contrast the softening point of PA 66 fiber is 235 ℃ and the melting point is 245 ℃. The glass transition temperatures of polyamide 6 and polyamide 66 were as determined by differential scanning calorimetry (DSC) to be 48 ℃ and 50 ℃, respectively.
Polyamide fibers have high crystallinity, orientation, and intermolecular forces, resulting in high strength. The breaking strength of polyamide filament for general textile use is 4.4-5.7 cN/dtex, and the wet strength is 85% -90% of the dry strength. The elongation at break varies with the variety, with strong filaments being slightly lower, about 20% to 30%, and ordinary filaments being 25% to 40%. The initial modulus of polyamide fiber is 17.6-44.1cN/dtex, which is lower than most other fibers and is prone to deformation during use.
Polyamide fiber is the most wear-resistant fiber among all textile fibers, with a wear resistance 10 times that of cotton, 20 times that of wool, and 50 times that of viscose fiber.
The moisture absorption of polyamide fibers is lower than that of natural fibers and synthetic fibers, but in synthetic fibers (except for vinylon), its moisture absorption is higher. Due to the presence of monomers and low molecular weight compounds, the moisture absorption of polyamide 6 fiber is slightly higher than that of polyamide 66 fiber. Under standard conditions, the moisture regain of polyamide 6 fibers is 3.5% to 5.0%, and that of polyamide 66 fibers is 3.4% to 3.8%.
The density of polyamide fiber is 1.14g/cm3, which is only higher than that of polypropylene and polyethylene fibers among all fibers. Although the dyeability of polyamide fibers is not as good as natural fibers and synthetic fibers, they are relatively easy to dye in synthetic fibers and can generally be dyed with acid dyes, disperse dyes, and other dyes.
2. Application:
The use of polyamide fiber includes civilian and industrial applications.
Civilian use includes clothing and household use, generally divided into woven, knitted, warp knitted fabrics, etc. Polyamide fiber can be used to make socks, underwear, shirts, sportswear, carpets, etc., and can be blended with cotton, wool, viscose and other fibers to make the blended fabric have good wear resistance. It can also be used to make bedding, outdoor accessories, furniture fabrics, etc. In terms of industrial applications, polyamide fibers are mainly used to make tire cords, transmission belts, transport belts, fishing nets, ropes, sail fabrics, sewing threads, filter cloth, non-woven fabrics, etc., involving transportation, fisheries, military and other fields.