Polyester is the trade name of polyethylene terephthalate fiber in China. It is a kind of polyester fiber, which is made by melt spinning method. There are many varieties of them, including filament and staple fiber, and filament has ordinary filament (including cord) and textured yarn; Short fiber can be divided into cotton type, wool type and medium length type.
1. Morphological structure
The section of ordinary polyester is round, and the longitudinal direction is smooth and straight Backpack webbing 。
2. Moisture absorption and dyeing
The hygroscopicity of self polyester is poor, and the moisture regain is only about 0.4% under general atmospheric conditions. Therefore, pure polyester fabric has a stuffy and hot feeling. However, less moisture absorption is a favorable characteristic for industrial fibers. The dyeability of polyester is also poor. It is difficult for dye molecules to enter into the fiber, and it is difficult for general dyes to dye. At present, disperse dyes are mostly used for high temperature and high pressure dyeing. The dyeability of cationic dyeable polyester has been significantly improved.
3. Mechanical properties
The breaking strength and elongation of polyester fiber are higher than those of cotton fiber, but they vary with the variety and drafting ratio. Generally, the filament has higher strength than the short fiber, and the strength and elongation of high drafting ratio are high and small. The modulus of polyester fiber is higher than that of hemp fiber. Excellent elasticity. Therefore, the fabric is crisp and wrinkle resistant, with stable size and good shape retention. The abrasion resistance of polyester is excellent, second only to nylon. But it is easy to fuzz and pilling, and the hair balls are not easy to fall off.
4. Chemical stability
Polyester is relatively stable to acids, especially organic acids. But polyester can only resist weak alkali, and the fiber will be damaged if it reacts with concentrated alkali at normal temperature or dilute alkali at high temperature. It has strong resistance to general organic solvents, oxidants and microorganisms.
5. Thermal properties
Polyester has good heat resistance and thermal stability. When treated at about 150 ℃ for 100o, there is only slight discoloration, and the strength loss is not more than 50%, while other conventional fibers are completely destroyed at this temperature for 200~300h. Polyester fabric is easy to melt into small holes when encountering fire, which may cause serious burns to human body.
6. Electrical properties
Polyester is an excellent insulating material due to its poor hygroscopicity and high specific resistance. However, it is easy to accumulate electric charges to generate static electricity and absorb dust. Dimensional bomb
7. Optical properties
The light fastness of polyester fiber is only inferior to that of acrylic fiber.
8. Density
The density of polyester is less than that of cotton and more than that of wool, about 139 gcm.
Although polyester was put into industrial production late, it is widely used in clothing, backpack webbing, decoration and industry due to its many excellent properties. The short fiber can be blended with cotton, wool, silk, hemp or other chemical fibers for clothing, decoration and other filaments, especially the textured silk used for knitting and weaving to make various simulated inner and outer garments. Filament is also widely used in tire cord, industrial rope, transmission belt, filter cloth, insulating material, sail, tent and other industrial products due to its good physical and chemical properties. With the continuous application of new technologies and processes, polyester fibers are modified to produce antistatic, anti fuzzing and pilling, cationic point dyeable polyester fibers. Polyester has a rapid development, high output and wide application.
