Every packaging paperboard has its own unique set of requirements. How much stress does the packaging need to withstand? Does the packaging have a certain look and feel? Is the paperboard folded to make a package? Is the packaging in direct contact with food, liquid or pharmaceuticals?
These are some of the questions UPM Pulp’s Technical Customer Service Manager Niklas Keskinen asks regularly in his quest for the best reﬁning and furnish solutions.
“In packaging paperboards you can use a variety of different ﬁbres more diversely than you might in other end use areas. There are numerous options you might consider depending on what you want to achieve with your packaging board. And that is exactly the reason why having a wide pulp portfolio enables us to better ﬁnd the optimum ﬁbre mix for our customers. We offer a full package,” Niklas says.
The right pulp for the right layer
Producing packaging papers is a balancing act of ﬁnding the best combination of chemical and mechanical pulps for the different layers of board. Mechanical pulp is usually used in the middle layer of paperboard to give it bulk. The choice of pulps for the top and bottom layers greatly depends on what will eventually be inside the package.
“Chemically bleached hardwood gives good opacity, formation and surface properties if the board will be coated or printed. In addition, our birch pulp UPM Betula provides good bending stiffness as well as cracking and folding resistance,” Niklas says.
Softwood pulps are most often used to improve runnability in the board machine and subsequent converting operations, but sometimes the content of the package sets the bar higher.
“If you are producing, for example, liquid packaging board or paper cups you must reach higher strength properties and therefore more softwood is used. In this case the greater softwood content provides folding, tensile and burst strength.”
Niklas says that working with different packaging paperboard producers has been very rewarding. He welcomes the challenge and opportunity to develop customers’ packaging solutions together.
“The topics we are working on are diverse from the technical point of view. We make sure our pulps perform as intended in every part of the value chain.”
All UPM’s pulp mills have been certiﬁed in accordance with the ISO 22000 Food Safety Management standard.