The process of manufacturing PET release film involves several critical steps to ensure the film has the necessary properties for effective release applications. Here's a structured overview of the process:

1. Material Preparation

• PET Pellets Drying: Polyethylene terephthalate (PET) pellets are dried to remove moisture, preventing defects during extrusion.

2. Film Extrusion

• Melting and Extrusion: PET pellets are melted and extruded through a flat die to form a thick sheet.

• Quenching: The molten sheet is rapidly cooled on chilled rollers to solidify into an amorphous state.

3. Orientation and Stabilization

• Biaxial Stretching: The film is stretched sequentially in the Machine Direction (MD) and Transverse Direction (TD) at controlled temperatures to enhance strength and clarity.

• Heat-Setting: The stretched film is annealed at high temperatures to stabilize dimensions and reduce shrinkage.

4. Surface Treatment

• Corona/Plasma Treatment: The PET surface is treated to increase surface energy, improving adhesion of the release coating.

5. Release Coating Application

• Coating Methods: A silicone-based release agent is applied using techniques like roll coating, gravure, or spray.

• Drying (if needed): Solvent-based coatings may require drying to evaporate carriers before curing.

6. Curing

• Thermal or UV Curing: The coating is crosslinked using heat or UV light to form a durable, non-stick layer.

7. Post-Processing

• Slitting: The wide film is cut into narrower rolls using precision blades.

• Edge Trimming: Excess material is removed to ensure uniform width.

8. Quality Control

• Testing: Release force, coating uniformity, thickness, and defect inspection are conducted.

• Adjustments: Coating parameters may be tweaked to achieve desired release levels (light, medium, heavy).

9. Packaging

• Winding and Protection: Finished film is wound onto cores, packaged in dust-free environments, and stored under controlled conditions.

Key Considerations:

• Environmental Controls: Cleanrooms may be used during coating to prevent contamination.

• Additives: Optional additives like UV stabilizers or anti-static agents can be incorporated.

• Customization: Coating formulations and thicknesses are adjusted based on application requirements.

This process ensures the PET release film meets performance standards for applications in labels, adhesives, and industrial laminates.