Troubleshooting

TL;DR — If PR57:1 red ink looks fine on the printed web but bleeds into the LDPE layer during extrusion lamination at 320°C, the culprit isn’t solvent retention. It’s thermal dissolution-diffusion. Lithol rubine has a melting point around 360°C — close enough to 320°C that pigment molecules start dissolving into molten polyethylene at the nip. … Read more

TL;DR — NC-based gravure inks that thicken or gel above 35°C aren’t just “heat sensitive.” The real culprit is acid-catalyzed nitrocellulose degradation, kicked off by residual acidic groups on the pigment surface — especially barium and calcium salt lakes like PR48:2. Measure the pigment’s acid value. If it’s above 5 mg KOH/g, you’re sitting on … Read more