Just as people are aware of the electronics brand named “Apple”, so are most people familiar with the material called Lycra (spandex). Lycra was invented by Dupont as a stretchable synthetic fiber, made by a more complex technique than nylon. The most common brand neutral references to the material is spandex or elastane. While similar to nylon, it is much more stretchable. However, it is not as durable as nylon. A garment made completely of spandex would be prone to tears and have difficulty keeping form. This is why spandex is frequently blended with nylon, so that you get the benefits of both materials. I should point out that spandex is made in four different ways, and each method may result in some characteristic differences.
The percentage of spandex versus nylon results in different benefits and drawbacks that are important to be aware of when buying hosiery.
In hosiery textile production, the real challenge of it all is to come up with a proper blending of synthetic fibers to achieve the desired results. Do you want a super sheer soft material, or a durable deep opaque material? Selecting the right fiber types of specific denier and then weaving them together in a precise proportion will achieve very different results.
For the most part, the main concern is to determine how much spandex should be blended with nylon. You’ll typically see spandex percentages as low as 1 or 2%, and as high as about 20%. I’m not a textile engineer, but from what I gather the percentage of spandex above 20% begins to create a very stretchy but more fragile material. I also have to believe that there are some cost measures in place as well, whereby more spandex means a more expensive textile. Nylon is certainly cheaper than spandex.
However, there are some new factors that are allowing textile makers to create more stretchy material without sacrificing durability. You have probably heard of Lycra 3D. This is a stitching technique whereby a Lycra fiber is present on all four sides of a stitch. It helps promote 4-way stretch while promoting a higher level of durability. There is also another technique called “double covered Lycra.” The Lycra soft yarn is a polyurethane based Lycra Soft 520 denier yarn double covered with nylon high speed textured yarn in order to prevent twisting and to maintain elasticity after processing. It allows lighter denier fibers used in sheer styles to promote greater stretch and strength.
Why am I bringing this up? Well, it’s useful to be aware of the percentage of spandex in a given style of tights you’re considering. Typically a higher level of spandex will mean greater stretch, and so if you’re on the upper edge of a size, the fit may be fine due to the stretchability of the fabric. Likewise, less spandex will typically mean less stretch. In addition to the percentage of spandex, you must also consider the benefits brought with Lycra 3D and double covered Lycra. The combinations possible become quite impressive, yielding sheer styles that fit better while being run resistant, and opaque styles that have a more luxuriously plush feel and greater stretch to fit fully.