Heat-shrink film is used for the sale and transportation of various products, with its primary functions being to secure, conceal, and protect the goods. The shrink film must exhibit high puncture resistance, excellent shrinkability, and a suitable level of shrink stress. During the shrinking process, the film must not develop any pinholes. As shrink film is often employed outdoors, it is necessary to incorporate UV‑stabilizing agents.
　　PE, or polyethylene, is a transparent thermoplastic. There are three major types of PE: LDPE, HDPE, and LLDPE. Although these three polyethylenes share the same monomer, they are produced under different processing conditions, resulting in distinct polymer varieties with significantly different properties.
　　PE film is a highly resilient material that is difficult to shred using conventional plastic shredders. Because PE film is both soft and tough, it resists cutting; moreover, at high speeds, the elevated temperature of the cutting blades can cause LDPE to melt and adhere to the blade edges. For pelletizing PE, the film can be fed directly in strips into the extruder’s feed throat, where the screw’s shear action draws the material into the barrel, heats it to melt, and extrudes it for pelletization. Primary‑grade recycled PE can still be used for blown‑film production, suitable for non‑food and non‑pharmaceutical packaging, and is also widely employed in the manufacture of Oxford cloth and waterproof fabrics, with promising prospects.
　　PE heat-shrink film is widely used for unit‑case packaging of products such as alcoholic beverages, canned goods, mineral water, various drinks, and textiles. This product boasts excellent flexibility, strong resistance to impact and tearing, and is durable, moisture‑resistant, and features a high shrinkage rate.
　　PVC shrink film incorporates additional additives to enhance its heat resistance, toughness, and ductility. The top layer of this surface film is a coating, the middle layer consists primarily of polyvinyl chloride, and the bottom layer is a back‑coated adhesive. It is a synthetic material that is widely favored, highly popular, and extensively used around the world today. Among materials capable of producing three‑dimensional surface films, PVC is the most suitable choice.
　　Due to PVC’s unique properties—such as rain resistance, fire resistance, antistatic performance, and ease of molding—and its low‑cost, high‑output manufacturing profile, it is widely used in the building materials and packaging industries. Consequently, PVC films exhibit high transparency, excellent gloss, and a low shrinkage rate.