Thursday 27 December 2012

Kelheim Viscose for Dry and Wet Nonwovens

Philip Wimmer of Kelheim Fibres GmbH, Kelheim (Germany) reviewed the changes in absorbency through Kelheim’s range of Italian fibres to illustrate that pure cellulose fibre can give from 1:1 to 4:1 water retention compared with cotton’s 0.5:1.  He then moved on to consider the possibilities of less absorbent, more hydrophobic types.  More crystalline fibres are less accessible to water and stronger, but this approach can do no more than halve the retention.  Adding non-absorbent fillers can do the same, but these more than halve the strength.  Chemical modification works, e.g. acetylation but the result is not pure cellulose.  Hydrophobic agents can be applied as finishes or added to the viscose, the latter approach giving a more permanent change in hydrophobicity which can resist washing and dry cleaning.  Kelheim have now developed such a product using an additive made from renewable, biodegradable raw materials which is also FDA approved for hygiene and food contact applications.

Ingo Bernt of Kelheim Fibres GmbH, Kelheim (Germany) ran through the properties of the Italian fibres again, the new additions this time being a 4dtex Leonardo smooth flat fibre and “Umberto”, a variable cross-section fibre giving an alphabet soup of shapes.  Umberto was not included in the written paper.  The finer Leonardo gives papers of higher strength and folding endurance than the 9dtex, but slightly lower transparency.  Anionic treatment as used to make the Verdi fibre boosts strength and folding endurance further.

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