Atsushi Tanaka, Jani Lehmonen, Pirjo Heikkilä, Ali Harlin, Jukka Ketoja
VTT Technical Research Centre of Finland Ltd
Foam forming process is suitable for producing a wide range of tailored nonwoven materials based on cellulose raw materials. Mixing, pre-processing and forming operations need to be compatible with the characteristics of the fibres (length, flexibility etc.) in order to guarantee homogeneity of the final structure. We have applied yarns and fibres up to 80 mm length with varied fibre stiffness and titer/fineness.
A significant advantage of the foam technology is the relatively easy formation of high-quality layered structures. This has been demonstrated by foam-forming multi-layer nonwoven fabrics from yarns and fibres. Layering is possible with just one forming step if the dimensions of yarns and fibres clearly differ. In this case, the foam flow carries small fibres through the yarn network leading to a smooth surface layer against the forming fabric.
The potential applications include technical textiles and fabrics used as layers in composite production. In technical textiles, alternating yarn and fibre layers can have different functionalities. Additional designed functionalities can be added with suitable surface treatments.