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A
new generation of cellulosic appeared in the market in December 1992 when
a commercial plant in the USA started to make a lyocell staple fibre,
based largely on European man-made fibre industry research. Subsequently,
two European production plants have opened.
Production
The process used to make lyocell fibres is a solvent spinning process.
The cellulose is dissolved in the solvent N-methylmorpholine n-oxide (NMMO)
containing just the right amount of water. The solution is then filtered
and spun through spinnerets to make the filaments, which are spun into
water. The NMMO solvent is recovered from this aqueous solution and reused.
Properties and End-Uses
The lyocell fibres, like other cellulosics, are moisture absorbent and
biodegradable. They have a dry strength higher than other cellulosics
and approaching that of polyester. They also retain 85% of their strength
when wet. Under certain conditions lyocell fibres fibrillate which enables
fabrics to be developed with interesting aesthetics. Non- fibrillating
versions are also available. Lyocell fibres are mostly used for apparel
fabrics, especially outerwear, but it has been shown that, due to the
fibrillating property some very interesting nonwoven fabrics can be made.
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