Why is silicone coated on PET protective film?

Applying silicone coating to PET protective film is a key process step to enhance its performance and meet diverse application needs. The following details the role of silicone coating, process flow, product introduction, and precautions:

I. Role of Silicone Coating
* **Enhanced Peel Performance:** The silicone layer imparts low surface energy to the PET protective film, creating a uniform peel force when in contact with the substrate (such as glass, metal, or plastic), avoiding adhesive residue or difficulty in peeling.
* **Improved Temperature Resistance:** Silicone has excellent high and low temperature resistance (-50℃ to 200℃), making PET protective film suitable for extreme temperature environments (such as electronic component soldering and outdoor equipment).
* **Chemical Stability:** Silicone exhibits good resistance to acids, alkalis, solvents, and other chemicals, protecting the substrate from corrosion or contamination.
* **Antistatic and Scratch Resistance:** By adding conductive agents or hard coatings, the silicone layer can impart antistatic or scratch-resistant properties to the PET protective film, meeting the needs of electronic screens, precision instruments, and other applications.

II. Silicone Coating Process Flow
* **Substrate Pretreatment:**
* **Cleaning:** Remove oil and dust from the PET surface using plasma cleaning or chemical solvents.

Corona Treatment: Improves the surface energy of PET and enhances the adhesion between the silicone and the substrate.

Silicone Formulation
Ingredients: Organosilicon resin, curing agent, solvent (e.g., toluene, isopropanol), additives (e.g., leveling agents, antistatic agents).

Viscosity Adjustment: Adjust the silicone viscosity according to the coating method (micro-groove, comma scraper, slot extrusion) to ensure coating uniformity.

Coating and Drying
Coating: Apply the silicone evenly to the PET surface, controlling the coating thickness (typically 5-30μm).

Drying: Remove solvent using an infrared or hot air circulating oven, controlling the temperature at 80-120℃, with the time depending on the coating thickness.

Curing
Thermal Curing: Heat at 150-200℃ for 1-5 minutes to fully cross-link and cure the silicone.

UV Curing: If using photosensitive silicone, rapid curing is achieved by irradiation with a UV lamp (wavelength 365nm).

Post-Processing
Rolling: After curing, roll up the silicone, paying attention to tension control to avoid deformation of the silicone layer.

Slitting: Cut to the specified size according to customer requirements. III. Product Introduction Optical Grade Protective Film Coated Silicone KL-9301
Product Advantages: Low tack, 1-2g peel force. 0.15-second ultra-fast automatic degassing. No primer required, excellent spreadability before curing. High transparency, light transmittance exceeding 94%. Passes double 85 test, leaves no residue under high temperature and humidity.

Application Areas: Protective films for electronic products, automobiles, construction, and glass surfaces. Aftermarket screen protectors, mobile phone protectors, process films, and other PET silicone protective film series products.

IV. Precautions
Substrate and Silicone Compatibility
The adhesion between PET and silicone must be verified experimentally to avoid delamination or separation.

For high transparency requirements, a low-yellowing silicone system should be selected.

Coating Uniformity Control
Regularly check the wear of coating equipment (such as doctor blades and rollers) to avoid coating thickness fluctuations.

Use an online thickness gauge (such as a laser thickness gauge) for real-time monitoring. Environmental Protection and Safety

Solvent-based silicone rubber requires an exhaust gas treatment system (such as an RTO incinerator) to meet VOC emission standards.

Operators must wear protective equipment (such as respirators and gloves) to avoid direct contact with the silicone rubber.

Storage and Transportation
The silicone rubber-coated PET protective film should be stored away from light and moisture, with the temperature controlled between 5-30℃.

Avoid severe vibration during transportation to prevent damage to the silicone rubber layer.