MR RADVAN mentioned (in the section on page 145 of attempts to produce a three-dimensional paper structure) several different approaches to the attempts at orienting the fibres in the Z-direction with the claim of increasing the bulk. As he also mentioned, this is of the greatest interest in the production of wet-laid non-wovens.
In addition to the method of upending some of the fibres, especially the short fibres and enmeshing them vertically in the web, a further method has been discovered. ⁽¹⁾ This uses crimped synthetic short-cut fibres in such a way that only a section of a fibre is located in the Z-direction and it is not necessary therefore to upend a complete fibre. Furthermore, this does not involve any after-treatment.