Effects of Moisture in the Lamination Process

Vernon asks:

I would like to know if there is anyone in the association who can give us advice. We currently have a client who performs laminations and has problems with the humidity of his product and as PT, we want to investigate if there is not an additive to reduce the capture of moisture from the environment in the corrugated.

If this respond does not completely solve the issue, please get back to us with more details. Pictures are always helpful.

Moisture issues can lead to anything from blistering and delamination, to warp, stacking issue and more. Ideally the litho sheets and the corrugated should be conditioned in the same atmosphere or room for 72 hours.  The moisture of printed labels is usually about 3% and corrugated sheets are usually 7-8%. Under the best conditions we target only a range differential of 2% points for good adhesion.  Wider differences can lead to tunneling (bubbling), cracking or delamination. Is curling the issue?

They may want to consider a faster setting PVA adhesive if there is a “moisture” problem.

— Ralph