What is the process of PET release film?

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.