What Solvent Attack on Film Labels Looks Like
Solvent attack is when the solvent in ink or varnish roughens the film surface, making the print hazy and coarse; in severe cases, the film surface wrinkles or shows dissolution marks. It is not ordinary poor adhesion: with poor adhesion, the ink comes off while the film remains glossy; with solvent attack, the film itself is damaged. First switch to a milder solvent or reduce drying, and do not increase pressure.
Solvent attack is when the solvent in ink or varnish roughens the film surface, making the print hazy and coarse; in severe cases, the film surface wrinkles or shows dissolved marks. It is not ordinary poor adhesion: poor adhesion means the ink comes off while the film remains glossy; solvent attack means the film itself is damaged. First switch to a milder solvent or reduce drying, and do not increase pressure.
What can be seen on the film
Where solvent attack occurs, it feels rough to the touch, looks hazy under side light, and pattern edges are not sharp. If unprinted film has been stacked against wet ink, blank areas can also be roughened, which shows that the solvent is migrating, not a dot problem on the printing plate. After tape is pulled, if the ink remains but the film is already roughened, it is still solvent attack.
Adhesion failure is just the opposite: tape pulls the ink away, and the film underneath is as glossy as unprinted areas. That calls for checking corona and whether the ink and film are matched, rather than first blaming the solvent for being too strong. The two can occur at the same time, but record them separately.
Handle separately
| Film surface | Ink layer | Change first |
|---|---|---|
| Roughened, hazy under side light | Ink still there | Solvent and drying |
| Still smooth | Tape can pull ink off | Corona and ink/film matching |
| Only splices or one roll roughened | Normal elsewhere | Solvent resistance of this roll of film; do not change the whole process |
Do this first this round
- Under side light, check whether blank areas are also roughened.
- If yes, first reduce solvent strength or drying temperature, then print a run and see whether the haze is still there.
- If the film is glossy and only the ink comes off, go check corona instead; do not keep trying different solvent formulas.
