(SYNTHETIC FIBER)

Spandex, invented in 1959, is a light weight, elastomeric, synthetic fiber in which the fiber forming substance is a long chain synthetic polymer comprised of atleast 85% of a segmented polyurethane.

Spandex when first introduced it revolutionized many areas of the clothing industry. They are compatible with other materials, and can be spun with other types of fibers to produce unique fabrics, which have characteristics of both fibers.

INTRODUCTION

The basic elements of nitrogen, hydrogen, carbon, and oxygen are synthesized with other substances to ethyl ester compounds in polymer chains of soft segments or sections that provide stretch and hard segments that holds the chains together.

"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.

Developing an alternative to rubber could solve both of these problems.

HISTORY OF SPANDEX FIBER

The first spandex fibers were produced on an experimental level by one of the early pioneers in polymer chemistry, Bayer.

The final development of the fibers were worked out independentlyby scientists at Du Pont and the U.S. Rubber Company.

Du Pont used the brand name Lycra and began full scale manufacture in 1962. They are currently the world leaders in the production of spandex fibers.

Spandex is produced as a filament or fused multifilament yarns in a variety of deniers.

Spandex fibers have a dog bone shaped cross section.

Multifilaments are partly fused together at intervals and are found in fibers with deniers of 40 and above.

The deniers of a spandex fiber ranges from 20 to 4300 and are determined by what the product use will be. 20 denier spandex, for example, is used in lightweight support hoisery, 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.

PHYSICAL STRUCTURE OF THE FIBER

Hollow spandex staple fiberSpandex fabric

Cross section of spandex fiber

The fibers are made up of numerous polymer strands.

Spandex consists of rigid and flexible segments in the polymer chain. The flexible segments give the fiber the stretch and the rigid segments hold the chain together.

When force is applied, the folded flexible segments straighten out and then return to their original position when the force is removed.

The proportions of flexible and rigid segments in the polymer chain determines the amount of stretch.

CHEMICAL COMPOSITION AND MOLECULAR ARRANGEMENT

A variety of raw materials are used to produce stretchable spandex fibers. This includes prepolymers which produce the backbone of the fiber, stabilizers which protect the integrity of the polymer, and colorants.

The methods used for the production of filaments include the initial step of reacting monomers to produce a prepolymer.

Once the prepolymer is formed it is reacted further in various ways and drawn out to produce a long fiber.

The solution dry spinning method is used to produce over 90% of the world's spandex fibers.

When they are first produced, spandex fibers are white. Therefore, colorants are added to improve their aesthetic appearance. Dispersed and acid dyes are typically used.

MANUFACTURING PROCESS

DRY SPINNING PROCESS

WET SPINNING PROCESS

• 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

• Hydrophobic fiber (1% moisture regain)

FIBRE CHARACTERISTICS

• Spandex fibers are vulnerable to damage from a variety of sources including heat, light, atmospheric contaminants and chlorine

• Available in fiber diameters ranging from 10 denier to 2500 denier

• Soft, smooth and supple

• Resistant to body oils, perspiration, lotions or detergents

• No static or pilling problems

• Can be easily dyed

Apparel and clothing articles where stretch is desired, generally for comfort and fit, such as athletic, aerobic, and exercise apparel

• swimsuits / bathing suits • net bodysuits• lingerie • ski pants, slacks, leggings, socks• Skinny jeans • belts

• Compression garments such as: • surgical hose, support hose• cycling shorts • wrestling singlet• One piece rowing suits• Foundation garments

• Home furnishings, such as micro bead pillows, etc.

APPLICATIONS

END USES / APPLICATIONS

Hand or machine wash in lukewarm water.

Do not use chlorine bleach on any fabric containing spandex. It can be washed or dry cleaned. As chlorine bleach causes yellowing of the fiber, use oxygen or sodium Perborate type bleach.

White spandex turns yellow from prolonged exposure to air. Rinse thoroughly.

Drip dry. If machine dried, use low temperature.

Ironing, if required, should be done rapidly. Do not leave the iron too long in one position. Use low temperature setting.

FIBER CARE TIPS

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