The cast film process for stretch wrap is a method of producing film through melt extrusion, flat-die casting, and rapid cooling. Utilizing linear low-density polyethylene (LLDPE) as the primary raw material, plastic pellets are melted and uniformly conveyed via an extruder to a flat die. The molten plastic forms a continuous film, which is then set by cooling rollers to produce a stretch wrap with uniform thickness and stable performance.
The production process involves proportioning and mixing raw materials, with functional additives-such as tackifiers and antistatic agents-incorporated according to product specifications. The blended material enters the extrusion system, where it is thoroughly plasticized at a set temperature to achieve optimal flow characteristics. Subsequently, the molten material is extruded through a precision die to form a sheet-like film of uniform thickness, laying the foundation for subsequent processing.
The extruded film immediately undergoes a cooling and setting stage; rapid temperature reduction via cooling rollers stabilizes the film structure and enhances surface gloss and flatness. The film is then stretched and adjusted using a traction unit to optimize its molecular structure, thereby improving tensile strength, elastic recovery, and tear resistance. Simultaneously, an in-line thickness monitoring system ensures product consistency by tracking thickness in real time.
After setting, the film undergoes edge trimming, surface treatment, winding, and packaging to produce the final cast stretch wrap. The casting process is characterized by high production speeds, a high degree of automation, and consistent film quality. It allows for precise control over thickness and performance, resulting in a stretch wrap that offers excellent transparency, self-adhesion, and packaging versatility-making it widely applicable in logistics, pallet wrapping, and industrial protection.