ponammmma spandex

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SPANDEX FIBRE & ITS APPLICATION IN TEXTILE SUBMITTED BY: POONAM YADAV 07TT031

Transcript of ponammmma spandex

SPANDEX FIBRE& ITS APPLICATION IN TEXTILE

SUBMITTED BY: POONAM YADAV 07TT031

Spandex is the first manufactured elastic fibre, and was introduced by DuPont under the trade name "Lycra" in 1959. Spandex is a generic name for a polyurethane fibre in which the fibre-forming substance is a long chain of synthetic polymer comprised of at least 85 percent of a segmented polyurethane. The most significant characteristic of spandex is its stretch ability. They are compatible with other materials, and can be spun with other types of fibres to produce unique fabrics, which have characteristics of both fibres. "Spandex" is the preferred name in North America, elsewhere it is referred to as "elastane". The most famous brand name associated with spandex is Lycra

The development of spandex was started during World War II. At this time, chemists took the challenge of developing synthetic replacements for rubber. Two primary motivating factors prompted their research:First, the war effort required most of the available rubber for building equipment. Second, the price of rubber was unstable and it fluctuated frequently. During research first development - durable elastic strand based on synthetic polymers (polyurethane). At the same time, scientists at Du Pont produced the first nylon polymers. Both are alternative to rubber but not so. The first spandex fibres were produced on an experimental level by one of the early pioneers in polymer chemistry, Bayer. Du Pont used the brand name Lycra and began full scale manufacture in 1962. They are currently the world leader in the production of spandex fibres.

Spandex is produced as a filament or fused multifilament yarns in a variety of deniers. Spandex fibres have a dog bone shaped cross section. The deniers of a spandex fibre ranges from 20 to 5400 and are determined by what the product use will be. 20 denier spandex, for example, is used in lightweight support hosiery, in which a large amount of stretch is necessary for the products use and durability. Coarser yarns, with a denier of 1500 to 2240 denier, have less stretch capacity and can be used for support hosiery tops, swimwear, and foundation garments.

Cross-section of spandex fibre

Spandex Fabric

Hollow spandex staple fibre

Trademark Lycra Vyrene Numa Glospan

Company E.I.du pont de nemours & Co. U.S Rubber Co. American Cyanamid Co. Globe Manufacturig Co.

y A variety of raw materials are used to produce

stretchable spandex fibres. This includes prepolymers which produce the backbone of the fibres, stabilizers which protect the integrity of the polymer, and colorants.

Spandex is a long-chain synthetic polymeric fiber. Two kinds of prepolymers are reacted to produce the spandex fibre polymer back-bone- the flexible macroglycols and the rigid Diisocyanate. Macro-glycol can be anything from among polyester, polyether, polycarbonate, polycaprolactum or some combination of these. These are long and flexible chain polymers having hydroxyl groups (-OH) on both ends, responsible for the stretching characteristic of spandex.

The polymeric diisocyanate is a shorter and rigid chain polymer, having an isocyanate (-NCO) group on both ends. This molecule provides strength to the spandex fibres. Catalyst such as diazobicycloctane is used to initiate reaction between the two types of prepolymers. Other low molecular weight amines are used to control the molecular weight of the fibres.

Spandex fibres are produced in four different ways:1. 2. 3. 4. Dry spinning Reaction spinning Wet spinning Melt spinning

The most commonly used method is the solution dry spinning that produces over 90% of the world's spandex fibres.

Step 1 The first step is to produce the pre-polymer. This is done by mixing a macroglycol with a diisocyanate monomer. The two compounds are mixed together in a reaction vessel to produce a prepolymer. A typical ratio of glycol to diisocyanate is 1:2. Step 2 The prepolymer is further reacted with an equal amount of ethylene diamine. This reaction is known as chain extension reaction. The resulting solution is diluted with a solvent to produce the spinning solution. The solvent helps make the solution thinner and more easily handled, and then it can be pumped into the fibre production cell.

Step 3The spinning solution is pumped into a cylindrical spinning cell where it is cured and converted into fibres. In this cell, the polymer solution is forced through a metal plate called a spinneret. This causes the solution to be aligned in strands of liquid polymer. As the strands pass through the cell, they are heated in the presence of a nitrogen and solvent gas. This process causes the liquid polymer to react chemically and form solid strands.

Step 4As the fibres exit the cell, an amount of solid strands are bundled together to produce the desired thickness. Each fibre of spandex is made up of many smaller individual fibres that adhere to one another due to the natural stickiness of their surface.

Step 5 The resulting fibres are then treated with a finishing agent which can be magnesium stearate or another polymer. This treatment prevents the fibres' sticking together and aids in textile manufacture. The fibres are then transferred through a series of rollers onto a spool. Step 6 When the spools are filled with fibre, they are put into final packaging and shipped to textile manufacturers.Wind up speeds ranges from 200-600m/min. Denier of individual filament ranges from 15-20

This is the most improtant spandex spinning process,after dry spinning. In reaction spinning, In the reaction spun process, a polyester or polyether is reacted with an excess of di-isocynate to form the urethane prepolymer, which is pumped through spinneretes at a constant rate into a bath of dilute solution of ethylenediamine in toluene. The ethylene diamines reacts with isocynate end groups on the resin to form long-chain cross-linked polyurethane elastomeric fibre. The final cross-linking reaction takes place after the fibre has been spun. The fibre is transported from the bath to an oven, where solvent is evaporated. After drying, the fibre is lubricated and is wound on tubes for shipment. Yarn speed upto 100m/min. Individual filament Denier ranges from 13-105.

1. Cross section- spandex filaments are extruded usually from circular orifices, but the evaporation of solvent or the effects of drying may produce non-circular cross-sectional shapes. This may take various forms. In the multi-filament yarns, individual filaments are often fused together in places. The number of filaments in a yarn may be as few as 12 or as many as 50;the linear density of filaments ranges from 0.1 to 3 tex (g/km). 2. Density: The density of spandex filaments ranges from 1.15 to 1.32 g/cc, the fibres lower density being based on polyesters.

3. Moisture regain: The moisture of fibres from which the surface finish has been removed lies between 0.8 & 1.2%. 4.Length:It can be of any length. May be used as filament or staple fibre 5.Colour: It has white or nearly white colour 6. Lustre: It has usually dull lustre. 7.Strength: Low strength compared to most other synthetic fibre. 8.Elasticity: Elastic properties are excellent. This is the outstanding characteristic of the fibre. 9.Heat: The heat resistance varies considerably amongst the different degrades over 300 F.

10.Flammability:It Burn slowly. 11.Electrical conductivity: It has Low electrical conductivity. 12. Breaking tenacity: 0.6 to 0.9grams/denier. 13.Toughness:The toughness of spandex fibres is unusually high. This is why this fibre exhibits such excellent abrasion resistance. nylon has exceptional toughness, and it is therefore interesting to compare a typical spandex fibre to a nylon fibre for this property. Nylon Spandex Tenacity , g/den 8.20 0.98 Elongation at break,% 25 500 Toughness index 1.20 2.55

1.Acid: Good resistance to most of acids unless exposure is over 24 hours. 2.Alkalies: Good resistance to most of the alkalies, but some types of alkalies may damage the fibre. 3.Organic solvents: offer resistance to dry cleaning solvents. 4.Bleaches: can be degraded by sodium hypo chloride. chlorine bleach should not be used. 5.Dyeing: A full range of colours is available. Some types are more difficult to dye than others.

Spandex is inserted in to fabrics in several forms:Bare form:Bare spandex is the common form for knit fabrics. Knit fabrics comprise the major outlet for spandex, although stretch wovens are in growing demand. Because of its very soft stretch Covering form:1. Single coveringIn single covering an inelastic filament or staple yarn is spirally wrapped around the spandex This property is valuable in operations such as weaving, where yarn rigidity is important to loom action. .

(a)

(b)

(c)

(d)

Forms of elastomeric yarns: (a)Bare, (b)Doble covered, (c) Coreplied, (d) Core spun

2.Double coveringIn which second inelastic yarn on top of the first in the opposite direction . Double covering is used today only where added expenses is justified by the advantages in durability and power.Core spun yarns Core spun yarns are made by simple adaptation of the common spinning process in which a roving of parallelized staple fibres is drafted and twisted on a spinning frame. Spandex at controlled high extension is introduced into the draft zone to become a continuous filament core at the center of the spun yarn. In core-spun stretch yarn, the spandex core is almost hidden by the spun fib sheath. This yarn is wound, knit, and woven at full extension like a hard yarn, since the inelastic sheath supports the load.

The most important property requirement for stretch garment is : Body comfort and fit Freedom of movement Breath ability Durability and Fabric elastic recovery is as important as stretching. The degree and direction of elasticity determines the end use of stretch garments. There are two methods by which stretch fabric can be manufactured. They are: 1. Spandex Core Cotton Spun Yarn Converted Fabric 2.Spandex Back Plaited Cotton Knitted Fabric

Apparel and clothing articles where stretch is desired, generally for comfort and fit, such as: at letic, aer

ic, a exercise a arel rt ae ic race ets its s i s its/ at i s its c etitive s i ear et all ys its s i a ts isc jea s l ves

slacks hosiery leggings socks diapers skinny jean belts dance belts worn by male ballet dancers and others

Compression garments such as: surgical hose support hose cycling shorts women's volleyball shorts wrestling singlet foundation garments motion capture suits Shaped garments Home furnishings, such as microbead pillows For clothing, spandex is usually mixed with cotton or polyester, and accounts for a small percentage of the final fabric, which therefore retains most of the look and feel of the other fibres. In North America it is rare in men's clothing, but prevalent in women's.Cyclist wearing spandex suit

Spandex is also being increasingly employed in nonwovens especially For the hygienic disposable and medical sectors such as:Medical support on the walker brace side with spandex belt fixer. 1.walker brace could protect foot, shank and ankle. Material: spandex fabric and foam medical knee support

Nonwoven disposable medical spandex face masks with earloops

Elastic crepe bandage with spandex .High absorbency, . High elasticity.

Wound dressing that are soft and have comfortable stretch. Knit- like stretchable gown sleeves and cuffs for use in protective and clean room apparel. Hygiene side panels for diapers and adult incontinence garments that are less irritating and fit better. Elastic bandages and low power wound care sleeves that may be less irritating than conventional material. Elastic protective covers that fit better, reducing the number of size needed. Elastic interlinings that are resistant to deformation. Elastic composites that are versatile and stretchable.

Spandex has become one of the most popular blending fabrics. Blending spandex with other fabrics creates: Excellent resiliency Dimensional stability Elastic recovery A better resistance to perspiration and body oils

It enhances the features of every fabric it s blended with to create a stronger, more versatile piece of clothing. Blended spandex fabrics feel better, fit better, and make us all look better. Many of the fabrics use a 3% to 30% spandex content, depending on the type of the garment That why spandex has become so widely used in the "Workout Wear and "Swim Wear" industries.

Light weight Can be stretched over 500% without breaking Able to be stretched repetitively and still recover original length. Abrasion resistant and resilient Stronger, more durable and higher refractive force than rubber Soft, smooth and supple Resistant to body oils, perspiration, lotions or detergents No static or pilling problems. Can be easily dyed

Disadvantage:

Spandex melts at 480F.

DuPont has developed a seamless Lycra. This makes for a smoother silhouette, and gives a curvier shape a more fluid line. Seamless spandex not only supports a fuller figure, it also provides the illusion of a more toned frame. The use of this seamless Lycra has become one of the most popular additions to the plus-sized in the fashion industry

Was i ca e e a r ac i e i l e ar ater. l t se c l ri e leac a fa ric c tai i s a e . It ca e as e r r clea e . s c l ri e leac ca ses ell i ft e fi er, se e rs i er rate t e leac . r l e e s re t air s l e r ite eca se White s a e t r s ell . i se thoroughl . ri r . If achi e rie , use low te erature. Ironing, if re uire , shoul e one ra i l , not lea e the iron too long in one osition. se low te erature setting

For fulfillment of the modern era requirements . A fibre having a thread of

fineness down to 50-100micro meter diameter, extensibility at least 500%, easy for wear comfort, rapid , forcefully & nearly complete recovery, tensile strength high enough to permit machine operations, heat resistance up to about 200degree C for short period, levels of whiteness, dye ability & physical property retention adequate for apparel use & maintenance that is spandex. Now for further development scientists are working on the stretch ability of the

spandex.

REFERENCES:

The Indian Textile Journal, January 2011.32-36 Man-made Textile in India, Feb 1999,60-66 Melliand International 3/2010,108-110 www.fiberjournal. Com, August 2007,22-23 Asian Textile Journal, September 2009 Textile Research Journal, January 2009 ,11-14 The Indian Textile Journal, March 2010, 22-27 Journal Of Textile Association- Sept-Oct, 2006, 103-106 The Indian Textile Journal, January 2011.32-36 Asian Textile Journal, Apr/May 2009,36-40 Internet. Hand book of Fibre Science and Technology : Volume 111 Edited by:- Menachem Lewin & Jack Preston.