Polyamide fiber is the first commercial synthetic fiber product of synthetic high molecular polymer. Nowadays, nylon products such as nylon fabrics have entered thousands of households.

    The most prominent advantage of polyamide fiber is that its abrasion resistance is superior to other fibers, followed by its good elasticity. Its elastic recovery rate is comparable to wool. In addition, it has the same corrosion resistance as polyester fiber and is not afraid of insects and mildew.

    The disadvantage of polyamide fiber is that the optical rotation resistance is slightly poor. If it is exposed to sunlight for a long time outdoors, it is prone to yellowing, the strength is reduced, and its shape retention is poor compared with polyester yarn. Therefore, the fabric is less upright. It also has a smooth fiber surface and a waxy feel. If you don't know the properties of nylon yet, then read on to the basic properties of nylon.

    1. Wear resistance: The wear resistance of polyamide fiber is the best among all textile fibers. Under the same conditions, its wear resistance is 10 times that of cotton, 20 times that of wool, and 50 times that of rayon. When 15% polyamide fiber is mixed into cotton spinning, its wear resistance is 3 times higher than that of pure wool or cotton.

    2. Breaking strength: The breaking strength of polyamide fiber long fiber for clothing is 5.0-6.4g/d. The industrial high-strength wire is 7-9.5 g/d or even higher, and its breaking strength in a wet state is about 85%-90% of that in the dry state.

    3. Elongation at break: The elongation at break of polyamide fiber varies according to the variety, the elongation of strong yarn is lower at 10-25%, and the yarn used for general clothing is 25-40%, and its wet state breaks The elongation is about 3-5% higher than the dry state.

    4. Elastic recovery rate: Polyamide fiber has excellent resilience. When the elongation of long fiber is 10%, its elastic recovery rate is 99%, while that of polyester is 67% under the same conditions, and that of the cord is only 32%.

    5. Fatigue resistance: due to the good elastic recovery rate of polyamide fibers. Therefore, its fatigue resistance is also good. Its fatigue resistance is close to that of polyester yarn and higher than other chemical fibers and natural fibers. Under the same test conditions, the fatigue resistance of polyester amide fiber is 7-8 times higher than that of cotton fiber. . Several times higher than Lei Zi.

    6. Hygroscopicity: The hygroscopicity of polyamide fibers is lower than that of natural fibers and rayon. However, in synthetic fibers, it is second only to polyvinyl chloride alcohol (PVA, vinylon) and higher than other synthetic fibers. The temperature of nylon 66 is 20 degrees Celsius, relatively When the humidity is 65%, the moisture content is 3.4-3.8. Nylon 6 is 3.4-5.0. Therefore, the hygroscopicity of polyamide 6 is slightly higher than that of polyamide 66.

    7. Dyeability: The dyeability of polyamide fiber is more difficult than that of natural fiber and violet, but it is still easier to dye than other synthetic fibers. Generally, it is dyed with acid dyes.

    8. Optical properties: polyamide fibers have birefringence (birefringence). The birefringence varies greatly with the elongation ratio. After sufficient extension, the longitudinal refractive index of nylon 66 fiber is 1.528, and the transverse refractive index is 1.519. The longitudinal refractive index of nylon 6 fiber is 1.580. The transverse refractive index is 1.530. Polyamide Fiber surface gloss is high. Titanium dioxide is usually added to the polymerization formatting.

    9. Optical rotation resistance: The optical rotation resistance of polyamide fibers is poor. The optical rotation resistance can be improved by adding a light resistance agent during polymerization to make fibers.

    10. Heat resistance: The heat resistance of polyamide fiber is not good. It turns yellow after 5 hours at 150 degrees Celsius, softens at 170 degrees, and begins to melt at 215 degrees. The heat resistance of nylon66 is better than that of nylon6, and its safe temperature is 130 and 90 degrees respectively. The maximum heat setting temperature should not exceed 150 degrees, preferably below 120 degrees. However, polyamide fibers have good low-temperature resistance. Even if they are used at a low temperature of minus 70 degrees, their elastic recovery rate does not change much.

    11. Chemical resistance: Polyamide fiber has good alkali resistance, but poor acid resistance. Under a normal room temperature, it can withstand 7% hydrochloric acid, 20% sulfuric acid, 10% nitric acid, and 50% caustic soda immersion, the result is not corroded. Therefore, polyamide fiber is suitable for anti-corrosion work clothes. In addition, it can be used as a fishing net, which is not afraid of seawater erosion. The life of a nylon fishing net is 3-4 times longer than that of ordinary fishing nets.