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Lyocell is a fabric most know better by its brand name

Lyocell owned by Lenzing Fibers of Austria. Lyocell heralds

the beginning of a new age in fibre technology. Completely

natural, Lyocell offers a unique combination of the most

desirable properties of manmade and natural fibres: Soft as

silk, strong as polyester, cool as linen, warm as wool and as

absorbent as cotton.

Basically, there are two broad categories of fibres: Natural

fibres like cotton, wool, hemp, ramie and silk; and artificial

fibres synthesised out of petrochemicals like nylon and

polyester. Lyocell falls somewhere in-between. The raw

material for Lyocell is cellulose from wood pulp, a mix of

hardwood trees like oak and birch, although Lyocell branded

Lyocell is made from eucalyptus trees, which are broken down

chemically in a soupy sludge that is squirted out a showerhead

spinneret and reformed as fibres. Lyocell is more accurately

described as a recovered or regenerated fibre, although

manufacturers make a distinction between regenerated fibres

and Lyocell, which they describe as a "solvent spun fibre"

that keeps the cellulose structure closer to that found in

nature.This makes it a natural fabric, and it is noted for its

durability and strength, in addition to its eco-friendly

manufacturing techniques.

History

The first fabrics made with wood pulp were made as far

back as the mid 19th century. They were not universally

accepted or very profitable. At the end of the 19th century, a

method for creating rayon out of wood cellulose became

popular, and rayon became one of the first manmade fibres,

as a silk substitute, and an inspiration to later produce Lyocell.

Success of rayon particularly in the latter 20th century fueled

interest in making other products from wood pulp.

The solvent-spun cellulosic fibre Lyocell was first produced

commercially in the US in 1992 by Courtaulds Fibers (now

Acordis Cellulosic Fibers), an international supplier of rayon.

The company used the brand name Lyocell. Lenzing AG

had acquired patents and research on Lyocell from

American Enka when it bought that company's rayon

operation in 1992. In 1996, Lyocell became the first new

generic fibre group in 30 years to be approved by the

Federal Trade Commissionas the properties and production

processes were unique to designate it as a separate fibre

group. Since then, Lyocell has realised increasing visibility

and acceptance in the home textile market, especially in

designer and better priced segment. Its versatility and

desirable properties provide many advantages, both

functional and aesthetic.

Federal Trade Commission Definition for Lyocell Fibre: A

cellulose fibre obtained by an organic solvent spinning

process where:

Lyocell (Tencel®

)

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1) “Organic solvent” means a mixture of organic chemicals

and water, and

2) “Solvent spinning” means dissolving and spinning without

the formation of a derivative

Although it is given a separate generic name, the FTC classifies

Lyocell as a sub-category under “Rayon.”

Fibre properties

A manufactured fibre composed of regenerated cellulose.

Lyocell has excellent properties of cellulose fibres. Lyocell

fabric feels very cool, moisture permeability; texture can be

changed to cotton wool, silk and all kinds of feelings. It is

having similar hand and drape as rayon, but is stronger, more

durable, and in many cases machine washable. It has a subtle

luster and is rich in colour. Lyocell possesses low shrinkage

characteristics, as well as good absorbency and wrinkle

resistant qualities.

Lyocell fibre characteristics

Texture

• Soft, simulates silk, suede, or leather touch

• Great for sensitive skin

• Loycell smooth fibre surface feels soft and supple against

the skin and its incredible wicking abilities keep the skin dry

Strength

• High tensile strength

• Excellent wet strength (2X rayon dry / 3X rayon wet)

• Lyocell fibres dry strength close to the polyester fibre, wet

strength decreased only 15 per cent

Moisture absorbent

• Highly absorbent

• It has natural breathability and 50 per cent greater moisture

absorption than cotton

• Swells radially when wet

• Due to its moisture management, it is also anti-bacterial

Dyeing

• Lyocell was created with colour in mind, because of the

fibres' high absorbency

• The fabrics can be dyed to high quality standards

• Very versatile fabric dyeable to vibrant colours, with a variety

of effects and textures

• Easily dyeable to strong colour-fast shades

Drape

• Good drapability

Temperature

• Does not melt

• Out performs cotton and rayon at high temperatures

Fibrillation

• This eco-fabric has controllable fibrillation (the very fine

hairs found on the outer fibres), which can be

manipulated into everything from suede-like softness

to a silky smooth finish

Dimensional stability

• Low shrinkage

• Good wash ability

• Can be hand washable

Bio-degradable

• The fibre is economical in its use of energy and natural

resources, and is fully bio-degradable

Durability

• Wrinkle resistant

Since Loycell is a manufactured fibre, the diameter and

length of fibres can be varied. Lyocell can be made into

micro fibres (very fine fibres), offering depth and body to

fabrics combined with luxurious drape. Short staple length

fibres give a cotton-like look to fabrics. Long filament fibres

are successful in silk-like end uses. Lyocell blends well with

other fibres including wool, silk, rayon, cotton, linen, nylon,

and polyester. It successfully takes many finishes, both

functional and those designed to achieve different surface

effects and dyes easily. Overall, Lyocell is a versatile fibre

with many desirable properties.

Important features of Lyocell fibres

Moisture

Unlike synthetic fibres Lyocell offers unique moisture transport,

as a result of nano technology. The nano technology of Lyocell

supports this natural fibre property, guaranteeing optimum

conditions for the skin. Synthetic fibres are unable to absorb

moisture into the inside of the fibre.

Lyocell naturally absorbs moisture and quickly releases it

again. This property guarantees a pleasantly dry sleeping

climate. The illustration shows that in contrast to cotton and

polyester fibres, Lyocell controls and regularly absorbs

moisture. Also it absorbs 50 per cent more moisture than

cotton. By contrast polyester does not absorb moisture.

Cotton Lyocell Polyester

The water is coloured in blue.

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In the bed environment, moisture transport is determined by

the climate in the room. In accordance with climate conditions,

Lyocell quickly absorbs and then releases moisture back into

the environment. Compared to other filling materials for bed

covers, it demonstrates the highest moisture absorption. Tests

show that this fibre still has free range to transport moisture

away from the body at humidity of 65 per cent.

The extent of which bed items are electrostatically charged

depends on the moisture content of the materials used and

their electrical conductivity. The moisture content in Lyocell

bedding prevents the build-up of static charge and prevents

the uncomfortable shocks that commonly occur in a dry winter

atmosphere.

Natural hygiene fibre

The moisture management of Lyocell nips the formation of

bacteria in the bud. Moisture is immediately transported to

the inside of the fibre. Hence, there is no moisture film to

aide bacterial growth. This bacterial protection works

without any chemical additives. However, with synthetic

fibres, the number of bacteria increases upto 2, 000 times.

Consequently, unpleasant smells are stopped before they

get a chance to start.

Lyocell bed linens are particularly

cool to the touch and soft on skin.

It supports these body functions

acting like a second skin. The

addition of Lyocell properties help

to alleviate skin irritation. It bed

linens are particularly cool to the

touch and soft on skin.

A smooth surface makes the bed linen silky and soft. It

advocates a pleasant feeling next to the skin as a result of

the fibre surface. If one compares the surface of cotton to

Lyocell the difference becomes perfectly clear. Wool tends

to have a scaly surface, while cotton is irregular and rough.

Lyocell, on the other hand is both, smooth and supple.

Perfect Moisture Management also puts a stop to the

unrestricted growth of mites in bedding. Research conducted

on mattresses (polyurethane foam with integrated Lyocell

powder) showed that a large portion of the applied mite

population died off. With conventional products, the number

of mites increased 17 times in a six week period. The

concentration of mites drastically declines due to Lyocell’s

management. It stores moisture and mites die out.

Due to Lyocell’s excellent moisture absorption mold

development is also prevented. A dry sleeping area prohibits

water condensation, which makes the formation of mold

impossible.

The skin sensor

More and more people are ailed by sensitive skin.

Environmental pollution and an upsurge in allergies have led

to increased interest in alternatives to conventional materials.

Typical properties of Lyocell fibre

Cotton LyocellWool

Property Units Typical values

Denier g/9000 m 1.25, 1.5, 2.2, 3.0

Cut length Mm 0.5 - 25 (precision cut)

Cross-section Round

Luster Bright, dull

Crimp per cm 0 - 2.5

Finish Various

Dispersibility in water Very good

Comparison with other fibres

Property Units Lyocell Polyester Rayon Cotton

Dry tenacity g/den 4.5 - 5.0 4.5 - 5.5 2.3 - 2.7 2.3 - 2.7

Elongation at break, dry Per cent 24 - 26 15 - 55 20 - 25 7 - 9

Wet tenacity g/den 3.9 - 4.3 4.5 - 5.5 1.4 - 1.8 2.8 - 3.4

Elongation at break, wet Per cent 16 - 18 15 - 55 23 - 35 12 - 14

Water imbibitions Per cent 65 - 70 N/A 90 - 100 44 - 55

Cellulose DP 550 - 600 N/A 250 - 350 2 - 3000

Initial modulus, wet g/den* 250 - 270 N/A 40 - 60 200

In many ways, Lyocell is more similar to cotton than it is to

rayon. Like other cellulosic fibres, it is breathable, absorbent,

and generally comfortable to wear. In fact, Lyocell is more

absorbent than cotton and silk, but less so than wool, linen,

and rayon. It can take high ironing temperatures, but like

other cellulosics will scorch, not melt, if burned, and is

susceptible to mildew and damage by silverfish. Cellulosic

fibres are not resilient, which means they wrinkle. Lyocell

has moderate resiliency. It does not wrinkle as badly as rayon,

*At 5 per cent strain

Polyamide Polyester Polypropylene Cotton (TENCEL®)

2000 x increase of bacteria

6 weeks 6 weeks

Startof trial conventional mattreswith (TENCEL®)

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cotton, or linen and a light pressing will renew the

appearance, if needed. Also, slight shrinkage is typical in

Lyocell materials. Stability, overall, is similar to that of silk

and better than cotton or linen.

It has strength and durability. It is the strongest cellulosic

fibre when dry, even stronger than cotton or linen and is

stronger than cotton when wet. Lyocell is much stronger than

rayon when wet. This property of high wet strength usually

determines the extent to which fabrics can be machine

washed successfully.

Disadvantage of Lyocell

• It will shrink (approx. 3 per cent) after its first washing but

retain its shape after that

• The manufacturing process for Lyocell is more expensive

than cotton or rayon

• It is more expensive than most eco fabric alternatives

• This fibre has a relatively low surface energy, which makes

it difficult for dyes to bind to it. This can cause fading

• Although these fibres themselves are eco-friendly, some

manufacturers use processes such as enzyme baths,

chemical processes, and dye treatments that are in no way

"green." These chemical treatments can cause allergies

in people with sensitivities

Environmental friendliness

Lyocell fibre comes from nature. Thus every bed article made

with Lyocell has a botanic origin. Eucalyptus wood is used as

raw material and is a product of the photosynthesis of plants.

In addition Lyocell has an eco-friendly manufacturing process

with a closed-loop production cycle. The solvent used is

recycled by upto 99.7 per cent.

The manufacturing process of Lyocell has an extremely low

impact on the human environment when it is produced.

Eucalyptus wood from sustainable forestry plantations are

used for the production of Lyocell. The cultivated land cannot

be used in any other way for agriculture. Cotton is grown on

valuable land that could otherwise be used for harvesting

food. The yield of fibre is on average six times higher than

cotton. Moreover, cotton agriculture needs upto 20 times

more water than Lyocell.

Conclusion

Lyocell is a godsend for anyone with sensitive skin. The

combination of a smooth fibre surface and excellent

moisture absorption creates a positive environment for

healthy skin, making Lyocell ideal for anyone with sensitive

skin. The applications for these fibres are exceptionally

versatile, to some extent; it is available in home products

including bath towels, sheets, pillowcases, and window

treatments. The fibre can be used in every aspect of

sleeping – beginning with mattresses and mattress pads

to bed covers and linens, all the way to lingerie. Lyocell’s

universality makes it possible to enjoy a completely botanic

bed from nature.

Further, today the world demands for “Organic, eco-friendly

and bio-degradable” products. Lyocell is the

environmentally-friendly fibre, and, the first truly

revolutionary fibre introduced to the market since Spandex

40 years ago, is made from wood pulp. Virtually all of the

chemicals used in the production process are reclaimed.

The resulting fibre, Lyocell, is both bio-degradable and

recyclable. It’s an improved fibre, in terms of performance

and properties. Its outstanding, essential and desirable

properties make it suitable for development of a variety of

high value-added woven and knitted products, an

extremely broad market prospect for various end uses. It

is easy to conclude that the future scope for Lyocell fibre

is definitely vast

By Vasant R Kothari, Assistant Professor, NIFT,Bangalore and Shravani. N, MFTech Student,NIFT Bangalore (Author can be contacted @

www.vasantkothari.com)