Surface Treatment: When More Energy Doesn’t Mean Better Performance

Corona and plasma treaters are standard on silicone coating lines. Their job? Boost surface energy so silicone can anchor properly.

But there’s a common mistake: when things go wrong, teams often increase treatment power without asking why. The result? Over-treatment.

More isn’t always better!

Over-treatment can:
– Damage fiber structure in paper liners, leading to dusting and delamination
– Overheat PET film, causing shrinkage or stress cracking over time
– Cause backside treatment, where corona discharges wrap around the web edge and treat the wrong side
– Increase ozone generation, requiring additional ventilation or filtration
– Lead to rebound effects where high energy temporarily boosts anchoring, but accelerates long-term desiliconization

What matters is not just energy level, but:
– Treatment time (web speed through the treater)
– Electrode configuration and polarity
– Substrate thickness and dielectric behavior
– Ambient humidity and temperature
– Electrode cleanliness and wear

Paper and film liners behave very differently. A setting that’s perfect for 60gsm glassine can easily burn or deform a 38 µm PET film.

Tips for smart treatment:
– Match surface energy to silicone chemistry—not just to arbitrary dyn/cm targets
– Monitor both sides of the web to avoid backside treatment
– Log actual corona power delivered (kW·min/m²) rather than just kV settings
– Consider pre- or post-treatment anchoring tests to validate silicone holdout

Corona is a tool. Use it with precision!

Is your surface treatment dialed in—or dialed up?