Assignment No # 2

Fiber = TencelName = M Noman Raza

Discipline = TS = 1A

Textile = 176

Lyocell is a form of rayon which consists of cellulose fiber made from dissolving pulp (bleached wood pulp). It was developed and first manufactured for market development as Tencel in the 1980s by Courtaulds Fibres in Coventry, UK and at the Grimsby, UK pilot plant.The process was first commercialised at Courtaulds rayon factories at Mobile, Alabama (1990) and at the Grimsby plant (1998). In 1998 Courtaulds was acquired by Akzo Nobel, who combined the Tencel division with other fiber divisions under the Acordis banner, prior to selling them off to private equity (CVC Partners). In 2004 CVC sold the Tencel division to Lenzing AG, who combined it with their "Lenzing Lyocell" business but maintained the brand name Tencel. As of 2013, Lenzing AG is the only major producer of lyocell fibers.

The US Federal Trade Commission defines Lyocell as a fiber "composed of cellulose precipitated from an organic solution in which no substitution of the hydroxyl groups takes place and no chemical intermediates are formed". It classifies the fiber as a sub-category of rayon. The fiber is used to make textiles for clothing and other purposes.

History

• Lyocell (lyo from Greek: lyein = dissolve, cell from cellulose)

• Naturally regenerated 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

Introduction

•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.

Raw Material

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.

MANUFACTURING AND PROCESSING

• 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 fiber comes out.

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

• Drying And Finishing

• Fiber 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.

Flow Chart of MANUFACTURING

PROPERTIES• Soft, strong, absorbent , lightweight, breathable,

comfortable

• 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, dye able 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

• Resistant to sunlight , abrasion and aging

• Hand feel is similar to rayon

• 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