27 Feb 2023
WHAT IS SPANDEX? HISTORY OF SPANDEX
Spandex in the United States is a different generic name for a fiber, often better known by the consumer as the names of the trademarks.
The study of polyurethane began in 1937, in Europe, in Bayer's research laboratories, by Otto Bayer. In 1939 Paul Schlack obtains a high molecular weight polymer which allows to obtain fibers characterized by strong elongations and elastic properties. In 1951 W.Brenschede obtained the Vulkollan fiber through a process called “Wet Spinning” (wet spinning).
In 1958 the "Dry Spinning" process was developed in the DuPont laboratories in Wilmington. The first elastomeric fiber was patented in 1958 with the name of "fiber K" and subsequently branded with the LYCRA trademark; marketing began in 1962. At first, the Lycra fiber was used in medical stockings, also because the manufacturing process allows only very high counts to be obtained. The potential of elastomers is very promising right from the start; in 1964 a well-known Italian designer presents a spandex fabric for swimwear.
In the 1970s research focused on developing for obtaining finer counts, but it was in the early 1980s that elastomers entered in hosiery market, offering to stockings and tights a new wearability.
DID YOU KNOW THAT?
LYCRA fiber is never used individually, but always combined with one or more others natural or synthetic fibers. In this way the fabrics offer more elasticity and comfort for the user. Also, The garment will retain the appearance and hand of the main fiber. It can be used in different quantities, depending on the type of fabric or its application, bearing in mind that 2% is enough to improve the quality of the product, enhance the It can be used in different quantities, depending on the type of fabric or its application, bearing in mind that 2% is enough to improve the quality of the product, enhance the vitality, drape and shape recovery characteristics.
SPANDEX YARN AND ITS APPLICATIONS
Spandex can be used itself, with no pre-processing before applying into socks or weaving fabrics machines. Bobbins of spandex fiber is added knitting together with the structure of the main yarn - flat or textured yarns. Another kind of technique is knitting the spandex, itself or covered, inside the garment (working in vanisé), also forming a knit. It is generally used in alternating rows, i.e. every other row of stitches. Also, the covered yarn can be used in all courses, i.e. in all rows of the knit, for three-dimensional elasticity.
The covering of the spandex consists in wrapping this fiber with the main yarn of the stocking-nylon or other kind; then the spandex becomes the soul of the yarn.
The covering yarns processes consist in four kinds:
- Single covering: the nylon or other fiber is spirally wound around the spandex only once and with an average of 1,200-2,200 turns/metre; the higher the number of turns, the higher is the quality final yarn.
- Double wrapping: the spandex yarn is wrapped in two strands of nylon or other fiber, respecting clockwise, the other counterclockwise. The number of turns averages 2,400 turns/metre, but reaches up to 3,000 per meter in the highest quality yarns. It is used in yarns for the production of high quality sheer tights.
- Air Overlay: Stretched spandex and textured nylon are passed together through an air jet, thus at intervals interlacing the nylon to the spandex core.
- Core-spun: during the spinning process, spandex is covered with a set of discontinuous fibers.
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The covered yarn is obtained by winding the Fulgar polyamide in a spiral around the LYCRA® fibre. The polyamide yarn used can be parallel, multifilament or microfilament textured. The higher the number of turns, the higher the quality of the yarn obtained.
Bare spandex yarn is used in standard products. Bare spandex, but knitted as vanisè process, is used in standard products, in ultra-sheer or summer tights: the elasticity is indeed reduced, but it allows the creation of ultra-sheer tights. Covered spandex is aimed at the medium and high-end market segments: in fact, the more protected the spandex is, the more durable and expensive the pantyhose is; moreover, the garment is also very soft to the touch.
There is no pantyhose in 100% spandex, another fiber is always added in high percentages – nylon, cotton, wool and silk, blends – which forms the base of the pantyhose. Its essential feature is the high elasticity and the return force, which it maintains unchanged over time.
In other words, the spandex fiber can stretch up to eight times its initial length and instantly return to its initial condition as soon as the tension is released. Wearability and comfort are the first and most appreciated consequences of this property. The tights with spandex are close to the legs, while allowing absolute freedom of movement. It makes the tights more durable because they are more wearable: the fabric is never too tight or too tight, the two main causes of breakage. It does not require particular attention in washing.
To these basic characteristics, the manufacturers have added others characteristics to the spandex fiber such as resistance to chlorine, fumes, pollution, chemical and oxidant agents, molds and bacteria.
Circular mono and multifilaments.
From 8 to 1,880 dtex.
Brigtness, semi-transparent, transparent, dull. The greater or lesser sheen is determined by the use of bare or covered spandex. In pantyhose it also depends on the type of yarn that accompanies the spandex.
Elongation at break:
Above 200%; it is usually between 400 and 800%, depending on the type.