I. Production process
1. Raw material preparation
- Base material selection: Use high-purity PET (polyethylene terephthalate) slices as the base material to ensure the mechanical strength and thermal stability of the film.
- Additive preparation: Add antistatic agents, lubricants, stabilizers, etc. as needed to optimize the temperature resistance, scratch resistance and surface flatness of the film.
2. Melt extrusion
Mix the PET slices with additives and melt them at high temperature. Extrude them through a slit die to form a primary film layer with a thickness of 10-200 microns. Strictly control the temperature and pressure to ensure the uniformity of the melt.
3. Stretch orientation
- Middle direction stretching (MD): The molecular chains are arranged in the longitudinal direction through roller stretching to improve the tensile strength of the film.
- Transverse stretching (TD): Further transverse stretching to enhance transparency and dimensional stability, forming a biaxially stretched (BOPET) structure.
4. Coating process
- Release agent selection: Apply silicone oil, fluorine or silicone-fluorine mixed release agent according to application requirements to give the film surface non-sticky or controllable stickiness.
- Coating method: Slit coating, micro-gravure coating and other technologies are used to ensure uniform coating, and the thickness tolerance is controlled within ±0.5μm.
5. Drying and curing
The coated film is dried in a high-temperature oven to remove the solvent and cure the release layer. The temperature is set according to the type of release agent (such as the curing temperature of silicone oil is usually 120-180).
6. Slitting and packaging
According to customer needs, the large roll is slit into a specific width (commonly 120-800mm) and dust-proof packaging is performed to ensure no pollution during transportation.
.Product features
1. Excellent physical properties
- High mechanical strength: The biaxial stretching process makes the film tensile strength reach 150-250MPa, with excellent tear resistance, suitable for high-speed die-cutting processing.
- Dimensional stability: Low heat shrinkage (≤1.5%), can still remain flat at high temperature (≤220), suitable for high-temperature processes of electronic components.
2. Controllable surface properties
- Wide range of release force: By adjusting the release agent formula, a release force of 5-2000g/25mm can be provided to meet the peeling requirements of different adhesives.
- High cleanliness: There are no defects such as particles and bubbles on the surface, which is suitable for the protection of precision electronic components.
3. Diversified functions
Single/double-sided release, matte/transparent/color film are optional, and some products have anti-static, chemical corrosion resistance and other characteristics.
. Application fields
1. Electronics industry
- FPC (flexible circuit board): As a laminated isolation film, it prevents circuit adhesion and protects the surface coating.
- MLCC (multilayer ceramic capacitor): Used as a release carrier in the lamination process to ensure accurate separation of the ceramic layer.
2. Adhesive products
Tape and protective film: As a release substrate for double-sided tape and foam tape, it ensures that the adhesive layer is peeled off without residue.
3. Packaging and printing
- Thermal transfer and hot stamping: Transfer the pattern to the surface of plastic, metal and other materials through the PET release film to achieve high-precision decoration.
- Aluminum-coated packaging: Aluminum-coated transfer film used for food and drug packaging, which is both environmentally friendly and metallic.
4. New energy and automobiles
- Battery separator: Release layer in blade battery production to ensure electrode stacking accuracy.
- Interior protection: Temporary protective film in the production of automotive foam and sealing strips to avoid surface scratches.
5. Medical and industrial
- Medical dressing: Plaster release layer to ensure sterility and easy tearing.
- Industrial die-cutting: Precision die-cutting gasket material to improve stamping efficiency
.Future Development Trends
- High-performance: Developing products that are resistant to higher temperatures (>300°C) and ultra-thin (<10μm) to adapt to 5G and semiconductor needs.
- Environmentally friendly process: Promote solvent-free coating technology to reduce VOCs emissions, such as TDK's release film recycling program.
- Function integration: Combine UV resistance, flame retardant and other composite functions to expand into emerging fields such as automotive electronics and AR/VR
