1       The multilayer co-extrusion cast film process is an advanced technology that precisely composites multiple polymer melts within a die head and forms them into multifunctional films in a single step. Its core process involves: multiple polymer raw materials (such as barrier PA and heat-sealable PE) are melted and plasticized by independent extruders before being conveyed to a structurally precise multilayer co-extrusion die head. Multiple independent flow channel systems within the die ensure stable flow of each melt layer. These layers precisely converge in parallel laminar flow at the die's confluence zone, forming a composite melt curtain with controllable layer thickness. The composite curtain instantly solidifies upon contact with a high-speed cooling cast roll, directly producing structurally complete multilayer composite film.

2 The advantages of this process are evident. In terms of product performance, it achieves molecular-level fusion between layers, resulting in strong bonding strength. This completely eliminates defects commonly found in traditional dry lamination processes, such as delamination and bubbling. Furthermore, through flexible “sandwich” structure design, it can combine high barrier properties and high strength into a comprehensive performance package at optimal cost. Regarding production efficiency and environmental sustainability, it consolidates multiple traditional steps into a single process, significantly shortening production cycles and reducing energy consumption. The entire process requires no solvents or adhesives, enabling green and clean manufacturing. Although the initial equipment investment is higher, its long-term comprehensive cost advantages are evident through material savings, streamlined processes, and improved yield rates.

3 As the core component of this process, the performance of the multi-layer co-extrusion die head directly determines the quality of the final film. Its design advantage primarily lies in achieving true interlayer fusion and structural integration, ensuring product integrity. Second, it offers precise layer thickness control and flexibility, enabling micron-level adjustments for each layer while freely combining different materials to achieve customized performance. Additionally, it delivers outstanding production efficiency and environmental sustainability. Modularity and scalability serve as key advantages, allowing flexible adjustment of layer counts by adding or removing flow channel modules. This significantly enhances the equipment's adaptability to future product upgrades.

4 Core Technology of Multi-Layer In-Mold Co-Extrusion Dies. Anhui Jwell's accumulated technological advantages are manifested in: a precision multi-layer melt distribution system based on a “coat hanger-style” runner design, ensuring uniform flow rate, pressure, and velocity across the entire width of the die for each melt layer—a critical factor in achieving uniform film thickness. Secondly, independent runner temperature and pressure control technology enables zoned, independent regulation of each layer's runners, preventing interlayer turbulence caused by differing processing characteristics. Furthermore, controlling the stability of the layer convergence interface represents a core technical challenge. The design must ensure smooth laminar flow superposition at the convergence point, avoiding interface defects that directly impact film transparency and mechanical properties. Finally, advanced mold materials and surface treatment technologies—including specialized hardening, polishing, or coating processes applied to runner surfaces—enhance corrosion and wear resistance.

In Summary:The multi-layer co-extrusion cast film technology and its core die head design, developed by Anhui Jwell, deeply integrates materials science, fluid mechanics, and precision manufacturing through precise fluid distribution, independent temperature and pressure control, and stable interface fusion technology. This technology is not only crucial for producing high-end functional films but also serves as the core engine driving the related industries toward high performance, high efficiency, and green transformation.