Winding film and stretching film are used to wrap the sales and transportation of various products to protect and cover firmly. The two names refer to the same thing. The concept of winding film is broader. Winding film is also called stretching film. Some winding films can be stretched, and some winding films cannot be stretched, or the stretching rate is low. Therefore, stretching film belongs to the category of winding film.
Winding film is also called tensile film and heat shrinkable film. In the early stage of China, PVC winding film was produced with PVC as substrate, DOA as plasticizer and self-adhesive. However, its cost is high. The PE stretch film first takes EVA as the self-adhesive material and has taste, and then develops pibv and LDPE as the self-adhesive material. Now the base material is mainly LLDPE, including C4, C6, C8 and metal pempe.
From single layer to two and three layers; At present, LLDPE stretch film is mainly produced by tape casting, and in the early stage, LLDPE stretch film was mostly blown. This is because the tape casting line has the advantages of uniform thickness and high transparency, which can be applied to the requirements of high magnification pre drawing. Because single-layer tape casting can not do single-sided adhesion, its application field is limited. Single and double-layer casting is not as wide in data selection as three-layer casting, and the formula interest is also high, so the three-layer coextrusion structure is ideal. High quality tensile film shall have the characteristics of high transparency, high longitudinal elongation, high yield point, high transverse tear strength and good puncture performance.
The stretch film can not only meet the functions of moisture-proof and dust-proof, anti touch and sneak change, transparent display and so on, but also increase the appearance attraction of the product. It can also be used to replace all kinds of cartons, which not only saves the packaging cost, but also conforms to the packaging trend. Pull around film is widely used in the outer packaging of various products such as food, medicine, sterilized tableware, sporting goods, craft gifts, printing materials, hardware and plastic products, telephones, electronic appliances and so on.
