Three-layer Co-extrusion Blown Film Machine: Packaging Performance Upgrade Engine

Three-layer Co-extrusion Blown Film Machine:

Engine for Performance Upgrade in the Packaging Industry

In the modern packaging industry, plastic film is a key medium connecting products and consumers. As the core equipment for producing high-performance composite films, the three-layer co-extrusion blown film machine has become a vital driver for functional customization and cost optimization in the industry. By integrating the advantages of multiple materials, it breaks the performance limitations of single-layer films and provides efficient, eco-friendly packaging solutions for food, pharmaceutical, industrial and other fields.

I. Overview of Three-layer Co-extrusion Blown Film Machine

A three-layer co-extrusion blown film machine is equipped with multiple extrusion units. It plasticizes and melts three types of plastic raw materials (such as PE, PA, EVOH, etc.) separately, composites multi-layer melts evenly through a special compound die head, and blows into three-layer structural composite film.

Main components:

Three independent extruders: Process different raw materials respectively to ensure plasticizing quality.

Compound die head: Adopts precision runner design to make three layers fit closely with uniform distribution.

Cooling and shaping system: Air ring rapidly cools the bubble to stabilize film structure.

Traction and winding system: Adjusts film thickness and winds finished products neatly.

II. Working Principle: Full Process from Raw Material to Composite Film

The operation is divided into five key steps:

Feeding: Three material pellets enter corresponding extruder hoppers with accurate feeding volume controlled by formula.

Plasticization & Melting: Screws shear and heat pellets into uniform melt; temperature and pressure are strictly matched to material characteristics.

Laminating & Film Forming: Melt converges in the die runner to form an integrated three-layer molten bubble.

Cooling & Shaping: External air ring blows cold air to rapidly solidify the bubble into film.

Traction & Winding: Traction rollers stretch the film to target thickness, and the winder rolls up finished products orderly.

The whole process adopts PLC control system to adjust parameters in real time, ensuring uniform thickness and stable performance of the film.

III. Core Advantages

Compared with single-layer or double-layer blown film machines, three-layer co-extrusion boasts prominent strengths:

Compound performance: Complementary functions of each layer achieve synergistic effect.

Outer layer: LDPE for good printability

Middle layer: EVOH for oxygen barrier to extend food shelf life

Inner layer: LLDPE for excellent heat-sealing performance

This structure meets demands of meat fresh-keeping packaging and retort pouches.

Cost optimization: High-performance materials are only used in the middle layer, while low-cost general plastics are adopted for inner and outer layers, cutting raw material costs without sacrificing performance.

High efficiency: One-step forming eliminates subsequent lamination procedures, reducing energy consumption and labor cost with production speed up to tens of meters per minute.

Stable quality: Multi-layer structure makes up for defects of single materials, featuring uniform thickness, balanced tear resistance and puncture resistance.

IV. Application Scenarios

Three-layer co-extrusion film is widely used in various packaging fields:

Food packaging: Meat fresh-keeping bags, 121°C high-temperature resistant retort pouches, puncture-resistant snack packaging films.

Pharmaceutical packaging: Substrates for pharmaceutical plastic-aluminum composite film, inner layer material of infusion bags with moisture and oxygen barrier properties.

Industrial packaging: Heavy-duty packaging films for chemical fertilizer and feed bags, featuring tensile and wear resistance.

Agriculture: Greenhouse films with thermal insulation, UV resistance and aging resistance via three-layer structure.

Daily chemical packaging: Shampoo and cosmetic packaging films with superior printability and barrier performance.

V. Technical Trends: Intelligent & Eco-friendly Development

The three-layer co-extrusion blown film machine is upgrading in three major directions:

Intelligent manufacturing: Equipped with online thickness detection such as infrared sensors and automatic parameter adjustment system, realizing unmanned production and lowering error rate.

Environmental compatibility: Promotes three-layer compound technology for degradable materials like PLA and PBAT to produce fully degradable films, supporting carbon peaking and carbon neutrality goals.

High efficiency & energy saving: New barrier screw design improves plasticizing efficiency; optimized die head reduces melt loss and energy consumption.

Conclusion

The three-layer co-extrusion blown film machine represents not only technological innovation in packaging equipment, but also the epitome of industrial upgrading. Through professional material combination, it upgrades film function from single performance to customized multi-function, meeting modern packaging demands for safety, efficiency and environmental protection. With continuous technological breakthroughs, it will further drive the packaging industry toward intelligence and sustainable development.