The production of stretch film is usually achieved by adding adhesive additives such as PIB masterbatch to PE film material and processing it through casting. Thermoplastic film, with a certain degree of adhesion on the surface, makes it convenient to wrap the goods without sticking to them. Black stretch film is suitable for the outer packaging of valuable items and can effectively prevent theft. Stretch film has the functions of moisture-proof, dust-proof, anti fixing, and anti loss for wrapped products. Widely used for packaging cardboard pallets, long building materials, food containers, glass ceramics, fertilizers, cement, resin materials, fabrics, empty cans, solid cans, etc.
Stretch film is used in the sales and transportation process of various products. Its primary effect is to stabilize, cover, and maintain the product. It is necessary for stretch film to have high puncture resistance, outstanding shortening ability, and certain shortening stress. During the shortening process, the film must not have pores. Because stretch film is often suitable for outdoor use, it is necessary to use UV anti UV agents. Especially in the combination (bundle) packaging of irregular shaped items or products, it can not only meet the functions of moisture and dust prevention, anti contact and anti drop packaging, and clear display of products, but also increase the attractiveness of product appearance. It can also be used to replace various types of paper boxes, not only saving packaging costs, but also in line with packaging trends.
In the early stage, blown film is the main method for stretching film, which expands from a single layer to two or three layers; Currently, the production of stretch films is mainly based on the casting method. This is because the production of the casting line has the advantages of uniform thickness and high transparency, which can be applied to the requirements of high magnification pre stretching. Because single-layer casting cannot achieve single-sided adhesion, its application fields are limited. The selection of materials for single and double-layer extrusion is not as extensive as that for three-layer extrusion, and the formula cost is also high. Therefore, the plan of three-layer co extrusion is more reasonable. High quality stretch film should have high transparency, high longitudinal elongation, high yield point, high transverse tear strength, and good puncture performance.
