UV coating adhesion problem

joe pasky

Member
We've been doing strike-through coating on UV presses for more than a year now at several printers; it works very well. Specifically, the adhesion is excellent: passes the 'ANSI Scotch-tape test' with flying colors.

We'd like to use printers that don't happen to have a UV press. They print conventionally, let it dry 24-hours, then apply the two UV coating pairs to get the 'strike-through' effect. Looks terrific, but the adhesion tends to be only fair. The coating lifts-off the ink with Scotch-tape.

One of the printers has been working on this problem for the past month in consultation with his coating manufacturer and ink supplier. They came up with a set of wax-free inks and a coating pair that gave excellent results. They tested the adhesion; it was very good.

Until....

They mailed them to the client who tested the adhesion again...it was terrible. It lifted off with only the slightest effort with Scotch tape.

So, what happened during the several days between the time the sheets were produced and the adhesion was very good, 'til the time it was tested again several days later and failed.

Sigh...:(

Any insight would be greatly appreciated along with any suggestions of things to try that might solve the problem.

jjp
 
Last edited:

tamale

Active member
UV coating

UV coating

Ask your coating suppliers if they have a cationic coating.

it worked very well for us. Unfortunately I don't work there anymore and cant supply you with a supplier or product name.

Tamale
 

REYES1377

Well-known member
One question, is the conventional printer laying down a PRIMER AQ on top of the ink? If not that may be the problem.
 

jonprintz

Well-known member
Make sure that everyone doing a tape adhesion test is using the exact same tape & test method, preferably from the same batch. Different tapes / brands or test methods will give drastically different results.

Wax free inks & AQ primer will help.

The end usage of the product should be considered also. Is it going to be tape tested in the field?
 

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