Split fibre technology

It is also possible to obtain crimped fibres by the split-fibre technology in a different way. If a laminated film is produced by extruding the raw material or raw materials in such a way that the layers display during stretching stress-strain curves which do not coincide, then a spontaneous crimp can be obtained immediately after fibrillation without additional thermal treatments of the fibres. It is, of course, necessary that the layers adhere well to each other. If both layers consist of polypropylene or copolymers of propylene, this is no problem. However, if different polymers are used, the adhesion is usually insufficient. 

Very thin fibres for nonwovens can be produced by split fibre technology. Bicomponent fibres are processed into a nonwoven fabric and this is followed by a splitting process. The fibres may be split mechanically by water jet technology or by the chemical dissolution of one component which leaves fine fibres of the other component (Fig. 2.7). 

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