Varnish Adhesion Problem After a Delayed Period

[Louis]

Varnish Adhesion Problem After a Delayed Period
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Hi All,

I am a newby to Print Planet, but hope that someone could please assist in trying to determine the cause of varnish peeling off after a delayed period in time(3 weeks plus) after the varnish was applied by silkscreen process. When the varnish was applied adhesion was checked and it stuck 100%. A couple of days later the boxes were die cut on a Bobst and still no adhesion problems. About another 2 weeks later the varnish starts peeling off in the scores and if you do a scratch test the varnish easily comes off. The job had a UV primer on and when varnished showed absolutely no problems.

Please help as this one has me completely baffled.

Thanks

[turbotom1052]

not familiar with silk screen process but were the inks and primer wax free?

[kbarz]

louis in order to make our ink stick to the sheets we must use uv curable iks, and that is to include the varnish as well... kbarz

[jonprintz]

Louis,
The substrate is an important factor to mention when you are talking about ink adhesion. If you had to primer it before the ink would adhere that may be a bigger problem than the varnish that scratches off easily.

There is not enough detail of your job to begin to answer why the varnish is failing. My first thought, however, is that the varnish / ink combination is not compatible.

Jonathan