Guangdong Weirui Intelligent Equipment Co., Ltd
Working Principle of the Plastic Extrusion Coating and Laminating Unit
Release Date:
2026-01-28
The core of a plastic extrusion-lamination composite production line is to melt and extrude plastic pellets into a film, then thermally laminate this film onto a substrate to achieve either single-layer functional coating or multi-substrate lamination. The entire process is a continuous, solvent-free manufacturing operation, which is mainly divided into five key steps: Raw Material Melting and Extrusion First, thermoplastic pellets such as PE and PP are fed into the hopper. Inside the screw extruder, the pellets are conveyed by the screw and heated in the barrel to high temperatures—approximately 160–220°C for PE and 180–240°C for PP—where they undergo melting and plasticization to form a uniform molten polymer melt. After passing through a filtration unit to remove impurities, the melt is extruded through a T-die (also known as a die lip), forming a thin, uniformly thick molten film. Substrate Conveying and Pre-treatment Paper, nonwoven fabric, aluminum foil, or plastic film substrates are steadily unwound from their reels and guided by idler rollers and web-guidance systems to ensure precise positioning and smooth feeding. Some machines are equipped with corona treatment units that ionize and activate the substrate surface, enhancing adhesion between the substrate and the molten plastic film and preventing delamination after lamination. Lamination and Film Formation The molten plastic film extruded from the T-die is directly laminated onto the continuously moving substrate surface, after which the combined assembly enters the laminating nip. This nip consists of a heated roller and a pressure roller; by precisely controlling temperature and pressure, the molten plastic film is tightly bonded to the substrate while simultaneously cooling and solidifying to form a robust composite layer. Cooling and Setting The laminated material then passes through a set of cooling rollers to reduce its temperature, allowing the plastic layer to fully crystallize and set. This ensures the flatness and dimensional stability of the composite film, preventing shrinkage or deformation caused by residual heat. Slitting and Rewinding Once the composite film has been set, it is conveyed by traction rollers to a slitting unit, where it is slit to the desired width. Finally, a rewinding machine rolls the slitted film into finished rolls, completing the entire extrusion-lamination process.
The core of a plastic extrusion-lamination composite production line is to melt and extrude plastic pellets into a film, then thermally laminate the film with a substrate to achieve functional coating of a single-layer substrate or multi-substrate lamination. The entire process is a continuous, solvent-free production method and is mainly divided into five major steps:
Melt extrusion of raw materials
First, thermoplastic resin pellets such as PE and PP are fed into the hopper. They are then conveyed by the screw of the extruder and heated in the barrel to a high temperature—approximately 160–220°C for PE and 180–240°C for PP—where they melt and plasticize to form a uniform molten polymer melt. After passing through a filtration unit to remove impurities, the melt is extruded through a T-die (also known as a die lip), forming a thin, uniformly thick film-like melt stream.
Substrate Conveying and Pre-treatment
Base materials such as paper, nonwoven fabric, aluminum foil, or plastic film are smoothly fed out by an unwinding unit, guided and positioned by guide rollers and a web-guidance system to ensure even feed. Some models are equipped with a corona treatment unit to ionize and activate the surface of the base material, thereby enhancing adhesion between the base material and the molten plastic film and preventing delamination after lamination.
Laminating and Composite Molding
The molten plastic film extruded from a T-die is directly coated onto the surface of a continuously moving substrate, after which the combined assembly enters the laminating nip. The nip consists of a heated roller and a pressure roller; by precisely controlling the temperature and pressure, the molten plastic film is brought into intimate contact with the substrate, while simultaneously undergoing rapid cooling and solidification to form a strong, bonded laminate.
Cooling and Shaping
After lamination, the composite material passes through a cooling roller set to reduce its temperature, allowing the plastic layer to fully crystallize and set its shape. This ensures the flatness and dimensional stability of the laminated film and prevents shrinkage or deformation caused by residual heat.
Slitting and Rewinding
After shaping, the composite film is conveyed by traction rollers to the slitting unit, where it is slit to the specified width as required. Finally, a rewinder rolls the material into finished rolls, completing the entire laminating and composite process.
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