Meaning
Corona discharge treatment dosage measured per unit area defines ionization efficiency during polymer web surface modification. High discharge frequency raises reactive species generation while web speed dictates exposure duration. When speed drops excessively, excessive bombardment creates micro pitting and chain scission, ruining adhesion and causing delamination.
Converters set treatment power on extrusion coating lines immediately before lamination stations. A laboratory material specification demands rigid dyne level thresholds, whereas production lines experience ambient humidity shifts that alter surface energy values. Virgin polyethylene film responds predictably to high electrode currents, whereas regrind blends contain slip additives that consume reactive species and require higher generator output.
Plasma Uniformity
Electrode air gap geometry dictates discharge consistency across wide extrusion dies. Uneven electrode wear creates localized treatment dropouts that cause random ink rub off on printed packaging films. Technicians calibrate air gaps using feeler gauges during scheduled maintenance shifts.
Low airflow velocity allows ozone accumulation, which corrodes grounding rolls and accelerates equipment downtime.
Resin Degradation
Excessive energetic electron bombardment breaks polymer backbone chains and generates low molecular weight oxidized fractions. Weak boundary layers form when oxidized fragments migrate to the film surface and prevent adhesive wet out. Extruders mitigate this issue by monitoring power density limits relative to line speed.
Virgin resins tolerate higher energy inputs without surface damage, whereas thermal history variations in regrind stocks reduce structural resistance to over treatment.
Adhesion Yield
Bond strength between extruded polyethylene and aluminum foil layers depends directly on polar group population density. Laboratory testing measures peel force per linear inch under constant pull rates. Production facilities monitor dyne pen wetting values continuously to prevent packaging seal failures during heat sealing operations.
Low treatment levels fail lamination standards, whereas balanced power settings ensure durable composite structures.
