What are Elastomeric Fibers?
Garments that stretches with the human body, supports it and conforms to it, almost certainly contains elastomeric fibers. Elastomers are polymers possessing high extensibility, with rapid and substantially complete recovery. Elastomeric fiberes are able to stretch up to seven times their length with an immediate full recovery to their original state without relying on being a crimped or coiled fiber.

Elastomeric fibers are typically synthetic fibers containing at least 85 wt% of a segmented polyurethane. In general the fibers are characterized by high elastic recovery (up to 99% recovery) and high extensibility (up to 500%), to an extent that depends on their exact chemical composition and fabrication method used to produce them. There are four traditional thermoplastic elastomer types that can be used to produce elastomeric fiber, i.e., polyurethanes, polyester copolymers, styrene copolymers, and the olefinics.

In Europe, elastomeric fibers are often known as Lycra fibers (though other brands such as Roica and Dorlastan also exist), and in the United States they are known as Spandex. Other types of elastomeric fibers include:

• Elastodiene fibers
• Elastomultiester fibers
• A few types of polyolefin fibers

These are commercially less important than elastane fibers.

Elastomeric fibers have limited use when not blended with other fibers, but the sport swimwear industry capitalizes on the non-blended properties of pure elastane. When blended as a small percentage with other fibers usually at a level of around 2–4%, elastane give greater flexibility to a product. So that the resulting fabrics have a certain amount of stretch. Such fabrics are used for activity wear, as well as hosiery, intimate apparel and casual outerwear such as denim jeans and shirts.

Types of Elastomeric Fibers:
Elastomeric fibers are a type of synthetic fibers that exhibit high elasticity and are capable of returning to their original shape after being stretched. Elastomeric fibers include the crosslinked natural and synthetic rubbers. Here are some types of elastomeric fiber:

1. Spandex/Lycra/Elastane
2. Neoprene
3. Natural Rubber Latex
4. Polyester Elastane/PBT Elastane
5. Polyurethane (PU)
6. Elastolefin Fibers

Properties of Elastomeric Fibers:
The special properties of elastomeric fibers include superior oxidation resistance, excellent resistance to dry cleaning solvents, good dyeability, excellent retention of properties after exposure to ultraviolet light, excellent resistance to body oils, and excellent toughness that avoids the need for fiber protection during knitting. In a number of elastic textile applications, these characteristics of modern elastomeric fibers make them the materials of choice in elastic textile applications, replacing rubber fibers and creating new markets such as active sportswear, medical textile, and comfort stretch garments.

Other properties are summarized below:

1. Elasticity: This is the prime property of elastomeric fibers; they can be stretched four to seven times their original length with excellent holding power. The length of elongation is determined by the diameter of the yarn; the greater the weight of yarn the less extension.
2. Resilience: The fibers are very flexible, and their rapid recovery rate ensures a flat, crease-free fabric.
3. Absorption: Given elastane’s low absorption rate, a product made with 100% elastane will feel clammy next to one’s skin, which is why it is often blended with other fibers or core spun to enhance its absorbency e.g. with cotton.
4. Strength: The breaking point of elastomeric fibers will not be reached until it has reached full extension, which seldom happens under normal circumstances so, it is relatively strong and durable.
5. Draping: As the fibers are flexible and lightweight they have good draping properties.
6. Resistance: Elastomeric fibers are resistant to seawater, sunlight, shrinkage, mildew, insects, perspiration and most acids. An important aspect of elastane is that it is resistant to body oils, cosmetics and suntan lotion.
7. Susceptible: Bleach can yellow and weaken the fibers. However, swimming pools use a mild form of calciumhypochlorite that is not strong enough to damage the fabric; plus, the temperature of the pool water tends to be relatively warm, not hot. Elastanes are thermoplastic and will melt at high temperatures becoming tacky at 175ºc whilst at 150ºc they yellow and lose their elasticity. Ironing elastane quickly on a low temperatures setting is advisable.

Uses or Application of Elastomeric Fibers:
Elastomeric fibers have the ability to recover rapidly and completely from very high levels of stretch and over repeated stretch/relaxation cycles. That’s why it is widely used in clothing for comfortable reason. Uses of elastomeric fibers are given below.

Clothing, including socks, tights, stockings, bra straps and side panels, underwear, jeans, leggings etc. It is often used more in women’s wear than in men’s wear due to the tight-fitting garments women require. It is also used for sportswear, where high stretch and holding power is required, including dance wear, cycling wear, swimwear, rowing gear, wrestling tops and aerobics outfits. Lycra FreshFX is used for products that require all-day freshness. It can also be used in the medical field; for example, support stockings, bandages and orthopaedic braces. It can also be used for soft furnishings, such as mattress covers and three-piece suite covers.

Other applications are point out below:

References:

1. An Introduction to Textile Coloration: Principles and Practice By Roger H. Wardman
2. Fibers to Fabrics by Bev Ashford
3. Handbook of Textile fiber Structure
4. Volume 1: Fundamentals and Manufactured Polymer fibers Edited by S. J. Eichhorn, J.W.S. Hearle, M. Jaffe and T. Kikutani
5. Synthetic fibers: Nylon, Polyester, Acrylic, Polyolefin Edited by J. E. McIntyre
6. Handbook of Textile fibers: Man-Made fibers By J Gordon Cook

Author of this Article:
Sanjida Zannat
Dept. of Textile Engineering
BGMEA University of Fashion & Technology, Dhaka

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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.

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