UV varnish adhesion on hot foil

[Tomas]

Hello everyone.
Has anyone encountered the problem of UV varnish adhesion on hot foil?

What happened:
1. Printing was done on cellulose cardboard with oxidizing paints with a water primer.
2. Then hot stamping with gold foil was done
3. Then UV varnishing was done

The defect appeared almost immediately.
No material substitutions were made for this order
The order is repeated, in previous editions the defect appeared from strong mechanical impact, but this time the varnish peels off from the slightest deformation and scratching. It peels off like a cracked film.

What could have gone wrong?

 

[Asures]

There’s a lot of reasons why you had job failure.

-It cold be the dyne level of the foil applied. If it was too low, the adhesion of the UV coating may be been compromised.

-Over exposure of the UV Coating? That would make it brittle and easy to scratch.

-Not a flexible UV Coating was used. Was it applied screen or roller UV?

Here's just a few things to look at.

 

[Tomas]

I think you are right about these options:

1. Today I tested the hypothesis about overexposure - it turned out that even with the smallest dose of UV radiation,
scratching occurs with the same ease as with maximum doses.
Therefore, in this matter, everything is normal.

But when I checked the quality of the surface tension of the material (foil), the markers showed the presence of 30 Dyne.

As far as I understand, there should be at least 38 Dyne?

Tomorrow I will test this hypothesis.
I will put several other brands of foil under equal conditions and see if any other foil gives more than 30 Dyne.

And I am confident in the varnish itself - I have long tested it in different editions and it has enough flexible.

We apply the varnish with a roller system. Not with a screen.