PET/Silicone-Based Release Film for Fabricating Self-Standing Coating Film, CPETSRF

In high-tech manufacturing—specifically for advanced battery components, printed electronics, and multilayer ceramic capacitors (MLCC)—PET Release Film serves as an indispensable transient carrier. Its role is to support a wet functional slurry during precision slot-die or roll-to-roll coating, withstand the subsequent thermal drying zones, and then cleanly peel away without altering or contaminating the newly formed functional microstructure.

Unlike standard release liners used for basic label or tape applications, a PET release film engineered as a coating substrate faces harsh thermal and tensile stresses. (1) Thermal Dimension Stability: When coating functional slurries (e.g., solid-state electrolyte precursors), the web passes through long convection drying ovens often ranging from 100°C to 150°C. Standard PET will shrink, causing the wet coating to wrinkle, crack, or delaminate. High-end lines require Biaxially-Oriented PET (BOPET) that has undergone thermal heat-setting, limiting thermal shrinkage to <0.5% at $150°C for 30 minutes. (2) Thickness Uniformity (Gauge Band Control): If the base PET film has variations in thickness across its width, the gap between the slot-die lip and the film will fluctuate. For an ultra-thin coating (e.g., a 5 um separator or electrolyte layer), a variation of just ±1 um in the PET film can cause catastrophic defects in the coated layer's dry thickness.

Silicone-Based Release Films (The Standard): Coated with highly crosslinked polydimethylsiloxane (PDMS) networks, typically cured via platinum-catalyzed thermal addition or UV radiation. Silicone migration is the most critical threat in advanced battery or electronics labs. If the silicone layer is not 100% fully cured, unreacted silicone monomers/oligomers will migrate into your coated slurry. In lithium-ion or solid-state batteries, this microscopic silicone contamination acts as an electrochemical insulator, causing localized high resistance, poor wetting of the liquid electrolyte, and premature cell failure. Ensure the film specifies a Subsequent Adhesion Strength (SAS) / Residual Adhesion Rate of >95%, proving that negligible free silicone is transferring off the film.

Non-Silicone Release Films (The Advanced Solution): For applications strictly intolerant to silicone contamination (such as battery极片 protection, dry-electrode processing, or specific fuel cell components), Non-Silicone PET Release Films are mandatory. These utilize fluoropolymers (Fluorosilicone or pure fluoro-coatings), acrylics, or specialized alkyd resins. Fluorinated release films are especially required if the slurry you are coating contains highly aggressive organic solvents (like NMP) or pressure-sensitive silicone adhesives, as standard silicone-on-silicone interfaces will lock up and fail to release.

References:

1. Y. Zou, et al., The study of PET recyclable polymers as paper coatings, Progress in Organic Coatings, 2007, 60, 127-131
2. Y. Li, et al., Flexible non-adhesive PDMS/PET release film for reducing separation force in bottom-up vat photopolymerization 3D-printing, Applied Surface Science, 2026, 737, 166876