Polyester, commonly known as "polyester". It is a synthetic fiber obtained by spinning polyester made of organic diacid and diol polycondensation, which is a polymer compound. The biggest advantage of polyester fiber is that it has good wrinkle resistance and shape retention, and has high strength and elastic recovery. It is durable, wrinkle-resistant, non-sticky, and non-sticky.
(1) Color. Polyester is generally milky white with mercerized, the production of matte TiO2 before spinning, the production of pure white products need to add whitening agent, the production of colored yarn needs to add pigments or dyes in the spinning melt.
(2) Surface and cross-sectional shape. Conventional polyester has a smooth surface and a nearly round cross-section. If special-shaped spinnerets are used, fibers with special cross-sectional shapes can be made, such as triangle, Y-shaped, hollow and other special-shaped cross-sectional wires.
(3) Density. When polyester is completely amorphous, the density is 1.333g/cm3. When fully crystallized, it is 1.455g/cm3, usually polyester has a high degree of crystallinity, the density is 1.38~1.40g/cm3, and wool (1.32g/cm3) is similar.
(4) Moisture regain rate. The moisture regain rate of polyester in the standard state is 0.4%, which is lower than that of acrylic (1%~2%) and nylon (4%). The moisture absorption of polyester is low, so its wet strength decreases less, and the fabric has good washability; However, the static electricity phenomenon is serious during processing and wearing, and the fabric has poor breathability and moisture absorption.
(5) Thermal performance. The softening point T of polyester is 230-240 °C, the melting point Tm is 255-265 °C, and the decomposition point T is about 300 °C. Polyester can burn in the fire, curl, and melt into beads, with black smoke and aromatic smell.
(6) Lightfastness. Its lightfastness is second only to acrylic. The lightfastness of polyester is related to its molecular structure, polyester only has a strong absorption band in the 315nm light wave area, so the strength is only 60% lost after 600h of sunlight, which is similar to cotton.
(7) Electrical properties. Polyester has poor conductivity due to low moisture absorption, and the dielectric constant in the range of -100~+160 °C is 3.0~3.8, which is an excellent insulator.