For the converters, this change was revolutionary, far more than simply exchanging gravure lacquering for a film lamination. In fact, film laminating to paperboard had not been done before at the two Smurfit-Stone plants that supply P&G.
“We’ve added some steps in our converting plants to produce this carton,” says Mike Laurianti, Smurfit’s national accounts manager for P&G. One of those steps was the introduction of electron-beam curing of the adhesive lamination.
Because the process laminates a clear film over a gravure-printed paperboard, the adhesive had to not only create a strong bond, it also had to be transparent so the printed graphics would be enhanced. So, says Laurianti, there was a lot of testing and trials. Finally, Northwest Coatings developed a specific formulation for this application.
That wasn’t the last change in making good bonds. At the folder/gluer stage, where Smurfit adds the manufacturer’s sideseam, “we’re using flame treating, to assist in getting a good mechanical bond,” Laurianti points out. Smurfit declined to be more specific about its processes or press sizes. “We’d prefer to leave that to our competitors’ imaginations,” Laurianti said.
The GRX film’s acrylic coating is largely responsible for the higher gloss, says Bill Minnich of AET Films. Laurianti says the gloss level has improved by 60% or more compared with the press-applied varnish, but he points out that the surface is more vulnerable to scratching or marking. “Our plants developed some handling techniques specific to this material,” Laurianti adds.
See the story that goes with this sidebar: Film-laminated cartons deliver for P&G
