Lyocell fibre properties

Tencel fibre is characterised by its high strength both dry and wet as can be seen from Table 5.1. 

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Other treatments to give specific fibre properties can also be performed -in particular various chemical treatments are used to control fibre fibrillation (e.g. as for the Tencel AlOO and Lenzing lyocell LF grades). 

Lyocell fibres are converted to a very wide range of textile and industrial products. In many areas, the particular properties of lyocell lead to environmental benefits for customers during product manufacture and use. 

The inherent properties of lyocell fibres make them particularly suitable for less intensive laundering. 

However, since 1998 the Lyocell process has been used in Austria and the special feature of this process is the solution of the pulp which is in an organic solvent (NMMO = N-methyl-morpholine-N-oxide), instead of CS2/NaOH, which has the effect of eliminating the odorous and noxious emission of sulphurous gases. The properties of the produets from this Lyocell process are different to the standard viscose fibre, and therefore this process should not be regarded as an environmentally compatible alternative to the viscose process. 

Most fibres made from regenerated cellulose such as viscose, lyocell, and Celsol are characterised by stiffness as well as a fuzzy and uneven surface that makes fabrics susceptible to pilling, even over a short period of use. In order to modify the surface properties of cellulosic fibres and fabrics and to improve their quality biotechnological approaches based on specialised enzymes are widely used. Finishing processes, employing cellulases and xylanases, can replace a number of mechanical and chemical operations, which have been applied until now to improve comfort and quality of fibres and textiles. The principle of enzyme action in the finishing process is controlled hydrolysis of cellulose, in which impurities and fuzz are removed from the surface of fibres, without decreasing their mechanical tenacity or the elasticity of the fabric. 

The application of 2-3% omf (on mass of fibre) fixed resin appears to be optimal for easy-care properties, dependant on the fabric constmction and weight. Application levels of 2% omf are needed to stop fibrillation on domestic washing. In addition to the resin, the choice of softener can have a large effect on the easy-care performance of fabrics, and it is important to consider the whole formulation and build it up to give the required performance. Silicone micro-emulsions penetrate yams more than the macro-emulsions. Polyethylene dispersions aid sewing and build the handle of the fabric, whilst some soft acrylic-based chemicals can increase the abrasion resistance. It is also worth remembering that caustic soda or liquid ammonia treatment in preparation will help to increase the easy-care rating of lyocell fabrics. 

Regenerated fibres from cellulose - R on and viscose are regenerated cellulosic fibres. The issue that is often brought up about regenerated fibres is that the processing uses harsh chemicals and is environmentally damaging. Tencel is considered a more environment-friendly regenerated fibre, and it has different properties from rayon. Lyocell/ Tencel is a cellulose-based fabric from farmed trees. 

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