Corona Treated Polyester Film
- Material: BOPET polyester film
- Product type: corona treated PET film
- Appearance: clear, smooth, treated surface
- Thickness: 12 um to 188 um common range
- Treatment option: one side or two side corona treatment
- Surface tension: 50-54 dyne/cm typical treated side
Protective Film Rolls Company is a corona treated polyester film manufacturer for printing, coating, adhesive coating, and lamination surface preparation. This surface treated polyester film is made for converters who need PET to accept ink, primer, coating liquid, or laminating adhesive more evenly. The main checks are treated side, dyne retention, roll winding direction, storage condition, and matching with the actual ink or adhesive system used in production.
Product Overview
Corona treated polyester film is used when a PET surface needs to be ready for printing, coating, dry lamination, extrusion coating, or adhesive transfer. PET film itself is stable, but a clean-looking untreated surface does not always give enough wetting for ink, primer, coating, or adhesive. Corona treatment raises surface energy, so the liquid system can spread with less pull-back, beading, and weak contact.
Dyne level is one of the first details we check, but it should not be read as a final guarantee. A roll can look clear and smooth while the treated side performs poorly after long storage, dust exposure, or use with the wrong ink or coating system. In our sample checks, a treated side around 50-54 dyne/cm showed steadier wet-out than an untreated side around 38-42 dyne/cm. Actual performance still depends on ink chemistry, coating viscosity, drying temperature, adhesive type, line speed, and surface cleanliness. Before production, treated side direction, winding, and storage time should be checked, especially for reverse printing, narrow-width coating, or lamination after long stock holding.
Benefits
- Better ink wetting: The treated surface helps ink spread across the film instead of leaving fisheyes, rub-off areas, or weak printed spots.
- Better coating wet-out: Controlled surface energy supports smoother laydown for primer, release coating, acrylic coating, or functional coating.
- Stronger adhesive anchorage: The treated side gives laminating adhesive a cleaner prepared surface before bonding with another web.
- Lower delamination risk: Proper dyne level helps reduce weak interfaces in multi-layer converting, especially after drying, curing, or aging.
- Easier production checking: Dyne pens or wetting tension solutions help operators check surface readiness before printing, coating, or lamination.
- More accurate side control: One-side or two-side treatment can match printing side, coating side, adhesive side, and winding direction.
How does corona treatment help coating wet-out on polyester film?
Corona treatment helps coating liquid spread into a more continuous layer by increasing the surface energy of polyester film. When dyne level is too low, the coating may pull back, bead up, leave pinholes, or create weak anchor points after drying. In coating trials, we normally look at edge pull-back, streaks, bare spots, and tape-test behavior after curing. A good surface treated polyester film should be judged by how the real coating behaves on the treated side, not only by clarity, thickness, or roll appearance.
TDS
Item | Typical Value |
Base film | BOPET polyester film |
Thickness range | 12 um to 188 um |
Standard thickness tolerance | +/-5% |
Treatment side | One side or two side corona |
Treated side surface tension | 50-54 dyne/cm typical |
Plain side surface tension | 38-42 dyne/cm typical |
Dyne check method | Dyne pen or wetting tension solution |
Haze | <=3.0% depending on thickness |
Heat shrinkage | <=2.0% at 150 C for 30 min |
COF | 0.35-0.55 typical |
Winding direction | Treated side inside or outside by order |
Storage advice | Keep dry and clean. Retest after long storage |
What dyne level should be checked before printing or lamination?
The correct dyne level depends on the ink, primer, coating, or adhesive being used, so corona treated polyester film should not be selected only by thickness or clarity. Different liquid systems wet PET in different ways. For practical control, dyne level should be checked on the actual roll before mass production. A small print, rub, tape, or peel test with the selected materials is useful, especially when the roll has been stored for several months or will run on a high-speed coating or lamination line.
Production Line
Applications
- Reverse printing before dry lamination
- PET surface preparation before lamination
- Ink adhesion checking for printing trials
- Primer coating and functional coating carrier
- Adhesive coating substrate for tapes or labels
- Metallizing preparation where a treated surface is required
- Trial coating and dyne-level validation before mass production
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FAQ
Is corona treated polyester film the same as normal clear PET film?
No. Normal clear PET film focuses mainly on base film properties. Corona treated PET film is prepared for ink adhesion, coating wet-out, and lamination bonding.
Will the dyne level stay the same forever?
No. Dyne level can drop during storage because of time, humidity, contamination, or surface migration. Retesting before use is recommended.
Can one treated side be enough?
Yes. One-side treatment is enough when only one side needs printing, coating, or adhesive bonding. Two-side treatment is better when both surfaces need preparation.
Does a high dyne level guarantee adhesion?
No. Dyne level is a useful surface check, but final adhesion must be tested with the real ink, coating, primer, or adhesive system.
