Quantifying Erucamide and Oleamide Migration in Multilayer Barrier Packaging Films
Primary amides partition toward high-free-volume polyolefin plies, requiring chromatography and friction verification to prevent costly converting failures.
Corona Discharge
Meaning
High voltage electrical breakdown of air surrounding a conductor initiates corona discharge. This phenomenon occurs when electric field intensity exceeds the dielectric strength of ambient air, creating ionized paths. Charges accelerate toward dielectric surfaces, modifying surface energy through oxidation.
Surface Treatment
Manufacturers utilize this effect to improve adhesion on polyolefin films such as polyethylene or polypropylene. Non-polar polymers lack the chemical groups necessary for high-strength bonding with inks, adhesives, or coatings. Treatment generates polar functional groups like carbonyl or hydroxyl moieties by bombarding the polymer lattice with reactive species.
Uniformity across the web width dictates the quality of downstream printing or lamination.
Process Variable
Power density measured in watts per square meter determines the effectiveness of the treatment. Excessive intensity degrades the polymer chains, leading to brittleness and potential film breakage. Insufficient energy produces low dyne levels, resulting in poor wetting and failed coating anchorage.
Production lines track this metric against the known surface energy threshold required for a specific ink or adhesive system.
Economic Consequence
Operational costs depend upon the electrical energy consumed and the required dwell time under the electrode array. Maintenance of the ceramic or metal dielectrics prevents localized arcing that creates holes or burnt spots in the film. Recycled resin contains higher impurity levels that interfere with energy transfer, forcing adjustments to the station settings compared to virgin material.
Stability of the discharge field prevents premature failure of thin films during high-speed converting.