Polyester products have significant characteristics, ie, high durability, abrasion resistance, lightfastness, and chemical resistance (e.g. resistance to bleaches), and proper dimensional reversibility and stability, which makes the final products more durable. Because of its specific chemical structure, Polyester is crystalline. Furthermore, owing to the absence of active groups in its polymer and the low moisture absorption, it is highly resistant to most chemicals. The other significant properties of these fibers are colorfastness and no need for ironing. In addition, they are resistant to boiling and weak acids, as well as strong and cold ones, and dilute alkalis have no effects on them, whereas hot and strong alkalies would damage them.