LYOCELLTHE NEW AGE FIBRE

INTRODUCTION Lyocell (lyo from Greek: lyein = dissolve, cell from

cellulose)

Man made cellulosic fibres

Produced by regenerating cellulose into fibre form out of a solution (solvent spinning) of cellulose in an organic solvent

‘Organic solvent’ - mixture of organic chemicals and water

‘Solvent spinning’ means dissolving and spinning without the formation of a derivative

Lenzing AG. is currently (2013) the only major producer of lyocell fibres

Tencel is the brand name of Lyocell

RAW MATERIALS Cellulose • Most abundant natural resource on earth.

• It is obtained form wood pulp.

• Trees like Eucalyptus , bamboo and pine tree are used.

• Eucalyptus is primarily used to produce the Tencel fibre.

NMMO• Chemically produced from N methyl morpholine and hydrogen

peroxide

• Cyclic amine oxides such as N-methyl morpholine oxide have the capacity to dissolve cellulose in large capacities

• NMMO exists in several degrees of hydration.

• At room temperature it is a crystalline mono hydrate and melts at 72 degrees

• When heated at 100 C, mono hydrate NMMO is able to dissolve readily several percentages of high molecular weight cellulose

• Cellulose dissolution in NMMO is found to depend on:

– The temperature of the solution

– The water content of the mixtures

– The concentration and the degree of

– Polymerisation of the cellulose

MANUFACTURING AND PROCESSING

Preparing Wood Pulp• Hardwood trees are harvested and logs

are taken to mill.

• Wood is cut into small chip and fed into a chemical digesters which removes lignin and softens them into wet wood pulp.

• It is then washed with water, bleached and dried into huge sheets of cellulose and rolled onto spools.

Dissolving Cellulose

• Spools of cellulose are unrolled and broken into one square inches.

• It is then loaded into heated pressurized vessel containing N-methyl morpholine N-oxide.

• Cellulose dissolves into a clear solution.

Filtering• In Amine Oxide solvent, cellulose is dissolved into a clear solution.

• It is then pumped out and filtered.

Spinning• Cellulose is forced through the spinnerets and long strands of fibre comes

out.

• These fibres are then dissolved in dilute Amine Oxide solution and is later washed with water.

Drying And Finishing• Fibre is passed through drying area.

• In the drying area, water is evaporated and lubricant is applied which may be soap, silicone or other agent.

Solvent Recovery• After spinning and drying process, dilute solution is taken passed through

the evaporator where water is removed and amine oxide solvent is fed back to the Dissolving process.

PROPERTIES Soft, strong, absorbent

Fibrillated during wet processing to produce special textures

It has high wet and dry strength, it is stronger than Cotton and Wool.

Wrinkle resistant

Very versatile fabric, dyeable to vibrant colours, with a variety of effects and textures.

Can be hand washable

Simulates silk, suede, or leather touch

Good drapability

Biodegradable

Fine yarn counts can be spun

Comfort• Soft, smooth fibre.

• Ideal for apparel that contacts skin.

• Thermal retention is poor.

Appearance Retention• Resiliency is moderate- Wrinkles but not as severely as rayon.

• Shrinks, but not progressively.

• May have problems with fuzziness or piling.

Aesthetics• Lustre, length and diameter can be changed depending upon end

use.

• Processed to produce a range of surface effects.

• Offers unusual combinations of strength, opacity, absorbency.

Durability• Performs more like cotton than rayon.

• Strongest of cellulosic fibres.

• Unique combination of soft hand and good durability, produces comfortable, long-lasting textiles for apparel and interiors.

Care• Either gently machine- Washable or dry cleaned.

• Sensitive to acids.

• Resistant to mild alkalis.

• Sensitive to mildew and some insects.

• High dye affinity.

• High inherent whiteness- Bleaching is not necessary.

PHYSICAL STRUCTURE

The physical structure is a more rounded cross section & smoother longitudinal appearance than rayon.

 Since in the case of Lyocell we are just dissolving cellulose in NMMO and not making any cellulose derivatives, it has a different molecular structure than other regenerated cellulosic fibres.

The structure is ‘Homogeneous’ and ‘Dense’.

Cross Section

Longitudinal Section

APPLICATIONS Professional business wear.

Leotards

Hosiery

Casual wear

Upholstery

Window-treatment fabrics

Filters

Printers’ blankets

Specialty papers

Medical dressings

Conveyer belts for strength & softness

Botanic Tencel bed

Botanic Bed

COMPARISON WITH OTHER FIBRES

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