Polyester bag, also called Lock rope bag, drawstring bag, Binder bag, is a kind of packing bag. Most of the materials used are flannel, nylon, non-woven fabrics, etc. The drawstring bag is flexible and convenient to use, the product is light and portable, and the hand feels soft and mild. At the same time, various patterns and logos can be printed on the surface of the product according to the customer's needs. The size of the product can be set according to the specifications of the packaged product. Therefore, the applicability and universality of the drawstring bag are greatly enriched. Due to the environmental protection and durability of its materials, drawstring bag has also become a kind of eco-friendly bag nowadays, which is widely used in gifts, jewelry, mobile phones, shopping and other places.