Introduction to blown polyethylene film

Blown Polyethylene Film is a film product manufactured through a melt extrusion-inflation process.
1. The process is as follows: Plasticization and Extrusion: Polyethylene resin (such as LDPE or LLDPE) is heated and melted in an extruder, and a tubular billet is extruded from a circular die.

2. Inflation and Shaping: Compressed air is injected into the billet, causing it to expand laterally (a blow-up ratio of typically 2.5–3.0) while simultaneously pulling it longitudinally (a pull-up ratio of 4–6) to achieve biaxial orientation and enhance the film's mechanical strength.

3. Cooling and Winding: After cooling and solidification through an air ring, the film is flattened and rolled. Some portions may require corona treatment to enhance printability.

Core Characteristics:
● High Toughness and Barrier Properties: Biaxial stretching imparts the film with excellent tensile strength, puncture resistance, and moisture and oxygen barrier properties.
● Processing Flexibility: Suitable for food, pharmaceutical, and industrial packaging applications. Adjustments to the raw materials (such as the addition of lubricants) can be used to optimize opening and heat-sealing properties. All of our blown film equipment is a five-layer co-extrusion blown film machine, equipped with a multi-air outlet, high-efficiency, bidirectional cooling air ring, and an online thickness gauge.

Features include:
● High flatness: Utilizing a multi-air outlet, high-efficiency, bidirectional cooling air ring, the film bubble cools uniformly, eliminating "fisheyes" and "water marks." The online thickness gauge provides real-time control, with a thickness fluctuation range of ≤±3%.
● High functional adaptability: The multi-layer formulation design allows for customization of various high-barrier materials.
● Improved mechanical properties: With the same formulation, the five-layer structure, through layered reinforcement, increases the film's dart impact strength (preventing package breakage) and longitudinal and transverse tensile strength by over 20%, making it more suitable for heavy-duty packaging (such as FFS film).
● Overall cost optimization: Flexible adjustment of the interlayer ratio reduces the use of expensive materials (such as metallocenes), resulting in significant potential for thickness reduction (15–20% reduction in thickness at the same strength), thus saving raw materials.
● Enhanced production stability: Each extruder uses a single raw material as the main raw material, reducing the problems of poor plasticization and crystal point caused by blending, and the finished product consistency is higher.