The core of producing multi-layer composite functional sheets lies in the precise stacking and bonding of material layers with different properties to achieve comprehensive performance that cannot be attained by a single material.
The typical process starts with functional layer design, in which polymer resins (such as PE, PP, PA, EVOH) or special functional masterbatches are selected separately according to target requirements including barrier, sealing, strength, or optical properties.
Subsequently, co-extrusion technology is commonly adopted to synchronously extrude multiple molten polymers through a multi-channel die, where they bond tightly and take shape either inside the die or on laminating rolls. Coating or laminating processes can also be employed to apply functional coatings (e.g., barrier coatings, adhesives) onto a substrate, followed by composite bonding with other substrates (such as films, aluminum foils, non-woven fabrics) via hot pressing or curing.
Throughout the process, precise control is required over layer thickness, melt temperature, pressure, and laminating speed. Online inspection may be introduced to ensure interlayer adhesion strength and functional uniformity. Finally, an integrated multi-functional sheet is obtained through cooling, sizing, and winding.