That plastic bottle you tossed into the recycling bin yesterday could end up in the chair you’ll be sitting in tomorrow! Well, perhaps not quite that fast, but eventually. It may seem hard to believe, like many a well-spun yarn (story), but in the textile industry, it’s actually true. That’s because the basic component in the textile manufacturing industry—fiber—can be either natural or synthetic.
A fiber is a substance that’s significantly longer than it is wide. Natural fibers (known as staple fibers) develop or occur in the fiber shape and come from animal, vegetable and mineral sources, such as wool, silk, cotton and linen. Then there are synthetic, or man-made, fibers (known as filament fibers), which are cellulosic, thermoplastic and mineral in nature. Their chemical composition is significantly modified during the manufacturing process, and they are used to produce rayon, polyester, nylon and fiberglass. This is not the type of fiber your doctor tells you to eat for good health, but it definitely supports a healthy textile industry!
Is one type of fiber better than the other?
Similar to how both true and fabricated elements can go into spinning a good story or yarn, both natural and synthetic fibers can be spun into yarn in the textile industry. Yarn is simply a group of fibers twisted together to form one continuous strand, and then many strands are woven into fabrics for different products. There’s no such thing as “better” fiber; it’s just that the yarn created from natural and synthetic fibers can be used to make products that have different characteristics and strengths.
Why you love pulling on that wool sweater
Natural (staple) fibers are non-continuous fibers that are relatively short in length. A “short” staple fiber has a maximum length of 2.5 inches while a “long” staple fiber is over 2.5 inches in length. Because they’re not very long, these fibers must be tightly twisted together in the spinning process to form a long, continuous yarn.
Short staple fibers are spun into yarn using the cotton system, while the woolen or worsted system is used for long staple fibers (wool). Both systems involve steps to prepare the fiber through blending, straightening the fiber through carding and finally spinning the fiber into yarn. Staple fiber yarns are usually thick, fibrous, and without luster. When woven together, they produce fabrics known for their comfort, warmth, softness and appearance, like in your comfy sweater.
The power of synthetics
Man-made synthetic fibers are created from cellulosic, thermoplastic and mineral sources. Because of the manufacturing process, called polymer extrusion, filament fibers are really long, unlike staple fibers (although long filament fibers can also be cut up into staple length). By the way, silk, as an exception, is a natural filament fiber.
Filament fibers are thin, smooth and lustrous, and used to make filament yarn. Because filament fibers are less chaotic than staple fibers, their yarns need very low amounts of twist to hold them together. Filament yarns are used to produce fabrics that are strong, durable, able to withstand abrasions and versatile.
Remember our tossed water bottle? Let’s see how polymer extrusion actually transforms it into a synthetic chair covering.
Polymers are derived from the by-products of petroleum and natural gas. In polymer extrusion, our water bottle (along with many others) is first shredded into plastic flakes and, because it is a thermoplastic synthetic (meaning it softens and melts when heated), it is then melted into polymer chips. Non-thermoplastic cellulosics have to be dissolved in a suitable solvent. If they can’t be dissolved or melted directly, they must be chemically treated to form soluble or thermoplastic derivatives.
The polymer chips are then melted again to form a thick, viscous liquid that is forced (extruded) through the tiny holes of a spinneret to convert the solution into filaments (slender streams of polymer). These filament fibers are solidified, cooled and collected on a take-up wheel. The fibers are later stretched and used to make filament yarns. Finally, the filament yarn is woven into a synthetic fabric that, among other things, will become the covering for the seat you sit in.
Nature and synthetic working together
The textile industry is keenly attuned to the concerns around protecting the environment through environmentally friendly manufacturing processes and products. Just like the water bottle, natural and synthetic fibers are both recyclable.
Original article by Duvaltex - Guilford of Maine 1/8/2020