We talked to Mikko Rissanen, Director, Technology at UPM Specialty Papers, to get the inside story on this very clever paper.
1. Paper quality
“Today, it’s not uncommon for the line speed on a labelstock coater-laminator to reach 1000 meters a minute,” says Mikko, “so the most basic requirement of a release paper is for it to have sufficient strength and stability to ensure runnability at those rates – and beyond.”
The cleanliness of paper can also influence production. Impurities and loose particles can compromise the integrity of the silicone coating layer and affect the release properties of the paper. In turn, that could potentially slow down production in later converting and compromise efficiency because of the downtime needed to clean the coating head rollers. When a label comes to be printed further along the value chain, these impurities can also trigger alerts from print quality monitoring systems which are unable to distinguish between irregularities in the printing or spots on liner material – especially with filmic labels. Yet more downtime!
Dimensional stability is also important so it’s vital to be able to control curling and shrinkage. Paper is a material that expands with ambient moisture conditions and contracts when dried. However, in a converting process it is crucial that it behaves predictably. Drying, shrinking, remoisturizing, expansion and lay-flat have to be consistent across production lots.
