New MasterJet Pro headbox concept for specialty papers
Decorative paper for hard-wearing laminate flooring and furniture requires distinctive properties. A close cooperation between Voith and Felix Schoeller has led to a manufacturing breakthrough for this particular specialty grade.
Hard to believe, perhaps, but at the heart of the most hard-wearing, water- and scratch-resistant laminate flooring is a thin layer of décor paper. The most attractive designs require a specialty paper that meets the highest demands, and not just for appearances. Absolute smoothness, easy impregnability, and high resistance to mechanical and chemical loads are all necessary properties of such paper.
“Getting there requires a superior manufacturing process, quite different to other paper grades,” says Michael Haffke, technology manager at the Osnabrück mill of the Felix Schoeller Group, the renowned specialty paper manufacturer based in Germany. The customers of Felix Schoeller require a quality of paper that can be impregnated with a special resin to create the core of the high-pressure laminate. How the paper behaves in this step is important to the final results. “Any waviness in the paper structure and the quality suffers. When you get it right, the results are stunning,” explains Haffke. Thanks to a close cooperation with Voith, Felix Schoeller has most definitely got it right.
Over the years, as the machines speeded up, getting their décor paper to continue to lie absolutely flat became an issue. Felix Schoeller called on Voith for their expertise and support. Reinhard Leigraf, Process Technology Engineer for Special Papers at Voith, was in charge of the investigative process. Using light analyses, Felix Schoeller and Voith found the root cause. “The problem came from the heart of the paper machine: The turbulence generator within the headbox,” says Leigraf.
To understand where the problem stems from, it helps to take a closer look at décor paper for laminate flooring. Achieving the high opacity level needed to cover the underlying layers in laminate requires a lot of titanium dioxide. In decorative paper, 20% to 40% is necessary. Other specialty grades use maybe 10% to 15% of a much cheaper clay. The better you can distribute this titanium oxide, the less is needed.
But it is not just about cost-efficiency – it also has to be achieved without compromising paper quality. This is why the design and functionality of the turbulence generator define the lasting outcome on the finished flooring.
“Paper with this high amount of titanium dioxide has a very different rheology to graphic paper. We found that it is not good to have too much turbulence in the headbox for décor paper,” explains Leigraf. “So we designed a brand-new one, the MasterJet Pro with ModuleJet.” The adaptions to the headbox resulted in a more homogeneous distribution of fibers in the sheet and the desired quality of paper at the reel with a very good basis weight profile.
“This unique headbox design made such a difference to our production that we have since ordered another two,” confirms Hans-Christoph Gallenkamp, COO Felix Schoeller Group. A happy customer makes a happy supplier. And as Leigraf stresses, the same solution is now available for all manufacturers of décor paper: “By solving a tricky problem for one partner, we opened up new opportunities for all manufacturers of décor paper.” And not just for laminate flooring: the same advantages are achieved for furniture surfaces and kitchen cabinet panels. Since the new design was launched, more than eight orders have been placed from various manufacturers.