In order to attain their special characteristics, LVT are composed of several specific layers as mentioned. This is classically achieved by separately compounding each layer on a Buss Kneader and calendering inline. The individual layers are subsequently pressed together.
In this optimized process, the three-layer core of LVT flooring is produced with two extruders and two calenders. In the first Buss Kneader a PVC compound, to which high proportions of mineral fillers and other additives are introduced through side feeders and split-feed, is plasticized and homogenized. The pressure build-up for feeding a fishtail nozzle is realized by a flanged-on discharge extruder to ensure decoupling of the compounding stage. Subsequently in the first calender, the compound is applied to fibreglass matting. This is then fed into the second calender, where the PVC compound prepared in the second Buss Kneader is applied to the other side of the fibreglass matting.
The great advantage of this inline processing, compounding and sheet production, all at the same temperature, is that the thermally sensitive PVC material is treated gently without any intermediate cooling/heating steps. After the second calendering stage, the decorative and wear-protection layers are laminated onto the triplex core. This 5-layer laminate then passes through an embossing station and a tempering section to ensure dimensional stability, and is finally cut to size.
Thus, with Buss process expertise and the continuously enhanced strengths of the Buss Kneader, specific requirements are being met as always. Product characteristics are optimized with uniformly moderate shear rates that can be adjusted, if necessary, as well as intensive mixing processes. And layering through a fishtail nozzle enables cost-effective inline calendering. It is these advances that exemplify why Buss has always been the technological and market leader in compounding vinyl-based materials.