Spandex Fiber

Spandex Fiber

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  Presentation Topics Spandex
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  Definition: • Spandexis a synthetic polymer. Chemically it is made up of a long-chain polyglycol combined with a short diisocyanates and contains at least 85% polyurethane. These fibers are superior to rubber because they are stronger, lighter, and more versatile. In fact, spandex fibers can be stretched to almost 500% of their length. Spandex melts at 250°C. Spandex yarn
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  Types of spandexyarn: Core spun yarn Blend spun yarn 1. Bare yarn 2. Covered yarn 3. Core spun yarn 4. Blend spun yarn Bare yarn Covered yarn
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  History: • Spandexis a synthetic fiber invented in 1959 at DuPont's Benger Laboratory in Virginia. • The development of spandex was started during World War II . At this time, chemists took on the challenge of developing synthetic replacements for rubber. • In 1940 the first polyurethane elastomers were produced.
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  Molecular structure: •Spandex is a polymer, it’s macromolecular structure is made up of repeating units (mers) denoted by the x and n next to the parentheses in the structure. Each Spandex fiber will differ somewhat in length and composition depending on the exact value of x and n.
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  Characteristics of Spandex: • Light weight, soft, smooth, supple • Can be stretched over 500% without breaking • Able to be stretched repetitively and still recover original length • Abrasion resistant Stronger, more durable than rubber • Soft, smooth and supple • Resistant to body oils, perspiration, lotions or detergents • No static or pilling problems
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  Physical Properties ofSpandex Fiber: • 1. Cross section- Spandex filaments are extruded usually from circular orifices. 2. Density: The density of spandex filaments ranges from 1.15 to 1.32 g/cc, the fibers lower density being based on polyesters. 3. Moisture regain: The moisture of fibers 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 fiber 5. Color: It has white or nearly white color.
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  • 6. Luster: It has usually dull luster. 7. Strength: Low strength compared to most other synthetic fiber. 8. Elasticity: Elastic properties are excellent. This is the outstanding characteristic of the fiber. 9. Heat: The heat resistance varies considerably amongst the different degrades over 300 F.
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  Chemical Properties ofSpandex Fiber: • 1. Acid: Good resistance to most of acids unless exposure is over 24 hours. 2. Alkalies: Good resistance to most of the alkalies. 3. Organic solvents: Offer resistance to dry cleaning solvents. 4. Bleaches: Can be degraded by sodium hypochloride. 5. Dyeing: A full range of colors is available. Some types are more difficult to dye than others.
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  Raw Materials: •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. Polyethylene
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  Raw Materials: •The macro-glycol can be a polyester, polyether, polycarbonate, polycaprolactone or some combination of these. These are long chain polymers, which have hydroxyl groups (-OH) on both ends. The important feature of these molecules is that they are long and flexible. This part of the spandex fiber is responsible for its stretching characteristic. The other prepolymer used to produce spandex is a polymeric diisocyanate.
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  Manufacturing Process: Spandexfibers are manufactured in four different ways- 1. Melt spinning, 2. Reaction spinning, 3. Dry spinning, 4. Wet spinning. • The initial step in all these methods is that of reacting monomers to produce a prepolymer. Prepolymer is then reacted further, in a variety of ways, and drawn out to produce a long fiber. The most commonly used method is the solution dry spinning that produces over 90% of the world's spandex fibers.
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  Dry-spinning process: •Groups (-OH) on the macroglycols react with the isocyanates. Each molecule gets added on to the end of another molecule, and a long chain polymer is formed. This is known as a step-growth or addition polymerization. To initiate this reaction, a catalyst such as diazobicyclo octane must be used. Other low molecular weight amines are added to control the molecular weight of the fibers. Spandex spinning process
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  Wet-spinning process: •Additives must also be added. All of the stabilizers that are added to the spandex fibers are designed to be resistant to solvent exposure since this could have a damaging effect on the fiber. • 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. If the spandex fibers are interwoven with other fibers such as nylon or polyester, special dying methods are required. Wet spinning process
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  Uses of SpandexFiber : • Garments where comfort and fit are desired: Hosiery, swimsuits, aerobic/exercise wear, ski pants, golf jackets, disposable diaper, waist bands, bra straps , bra cup and bra side panels. Compression garments: Surgical hose, support hose, bicycle pants, foundation garments Swimming Dress
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  References: • http://www.fibersource.com/f-tutor/spandex.htm • http://en.wikipedia.org/wiki/Spandex • http://www.teonline.com/knowledge-centre/ spandex-fiber-production-process.html • http://textilelearner.blogspot.com/2012/01/mohair-or- angora-spandex-fiber.html
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  Md.Reazul Islam B.Scin Textile Engineering Daffodil International University Dhaka, Bangladesh. Email: [email protected]