Commercial Landed Cost Variance Mechanics and De Inkability Fee Surcharges in Packaging Grade Substitution
Commercial landed cost variance depends on sheet yield, press spoilage, and EPR de-inkability fee surcharges triggered by grade substitution.
Flexographic Inks
Resin Rheology
Liquid formulations based on polyamide or nitrocellulose polymers define flexographic inks, carrying pigments through low-viscosity application systems directly onto absorbent or film substrates. Polymer selection dictates drying speed and adhesion strength on non-porous surfaces like polyethylene or polypropylene films. Viscosity control remains essential during high-speed printing runs to prevent dot gain and ensure clean transfer from the anilox roller.
Pigment loading must balance colour density against fluidity requirements so that high-speed presses operate without excessive doctor blade wear. Solvent evaporation rates govern press stability and trap cleanliness on multi-colour jobs.
Solvent Retention
Residual volatile organic compounds within dried ink films compromise food contact safety compliance and seal integrity in flexible packaging laminates. Drying tunnels rely on heated air velocity to drive solvents below threshold limits before reels rewind under high tension. Trapped moisture or lingering alcohols plasticise the underlying polymer matrix, causing odour transfer and delamination during subsequent adhesive lamination processes.
Extended dwell times in drying zones reduce solvent levels but increase thermal stress on heat-sensitive substrates like thin low-density polyethylene films. Gas chromatography testing quantifies residual fractions against regulatory thresholds for food packaging applications.
Film Thickness
Deposited wet film thickness determines optical density and colour strength once dry, while directly influencing the drying energy required per square metre of printed web. Anilox cell volume controls the exact volume of liquid transferred to the printing plate, establishing limits for ink laydown. Excess transfer floods fine highlights and causes bridging in shadow areas, whereas insufficient volume yields washed-out tones and poor solid density.
Substrate surface energy, measured in dynes per centimetre, interacts with liquid surface tension to determine whether ink droplets spread evenly or pull back into discrete beads before drying occurs. Surface tension differentials between successive colours govern trap efficiency on wet-on-wet multi-station printing presses.