Yarn can be made from a number of
natural or
synthetic fibers, or a blend of natural and synthetic fibers.
Natural fibers Cotton of cotton The most common plant fiber is
cotton, which is typically spun into fine yarn for mechanical weaving or knitting into
cloth.
Silk Silk is a natural
protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of
fibroin and is produced by the larvae of the moth
Bombyx mori. Silk production is thought to have begun in China and silk thread and cloth manufacture was well-established by the
Shang dynasty (1600–1050 BCE).
Linen Linen is another natural fiber with a long history of use for yarn and textiles. Linen fibers are derived from the
flax plant.
Other plant fibers warp yarns being prepared for weaving in a modern textile factory Other plant fibers which can be spun include
bamboo,
hemp,
maize,
nettle, and
soy fiber. Other animal fibers used include
alpaca,
angora,
mohair,
llama,
cashmere, and silk. More rarely, yarn may be spun from
camel,
yak,
possum,
musk ox,
vicuña,
cat,
dog,
wolf,
rabbit,
bison, or
chinchilla hair, as well as
turkey or
ostrich feathers.
Synthetic fibers Some examples of synthetic fibers that are used as yarn are
nylon,
acrylic fiber,
rayon, and
polyester. Synthetic fibers are generally extruded in continuous strands of gel-state materials. These strands are drawn (stretched), annealed (hardened), and cured to obtain properties desirable for later processing. Synthetic fibers come in three basic forms: staple, tow, and filament. Staple is cut fibers, generally sold in lengths up to 120 mm. Tow is a continuous "rope" of fibers consisting of many filaments loosely joined side-to-side. Filament is a continuous strand consisting of anything from one filament to many. Synthetic fiber is most often
measured in a weight per linear measurement basis, along with cut length. Denier and Dtex are the most common weight to length measures. Cut-length only applies to staple fiber. Filament extrusion is sometimes referred to as "spinning," but most people equate spinning with spun yarn production.
Yarn from recycled materials T-shirt yarn is a recycled yarn made from the same fabric as is used in T-shirts and other clothes. It is often made from the remainder fabric of clothing manufacture, and therefore is considered a recycled and
eco-friendly product. It can also be made at home out of used clothing. The resulting yarn can be used in knitted or crocheted items.
Comparison of material properties in the UK In general, natural fibers tend to require more careful handling than synthetics because they can shrink,
felt, stain, shed, fade, stretch, wrinkle, or be eaten by
moths more readily, unless special treatments such as
mercerization or super washing are performed to strengthen, fix color, or otherwise enhance the fiber's own properties. Some types of protein yarns (i.e., hair, silk, feathers) may feel irritating to some people, causing
contact dermatitis,
hives, or
wheezing. These reactions are likely a sensitivity to thicker and coarser fiber diameter or fiber ends. In fact, contrary to popular belief, wool allergies are practically unknown. According to a study reviewing the evidence of wool as an
allergen conducted by Acta Dermato-Venereologica, contemporary superfine or ultrafine Merino wool with their reduced fibre diameters do not provoke itch, are well tolerated and in fact benefit
eczema management. When natural hair-type fibers are burned, they tend to singe and have a smell of burnt hair; this is because many, like human hair, are protein-derived. Cotton and viscose (rayon) yarns burn as a wick. Synthetic yarns generally tend to melt, though some synthetics are inherently
flame-retardant. Noting how an unidentified fiber strand burns and smells can assist in determining if it is natural or synthetic, and what the fiber content is. Both synthetic and natural yarns can
pill. Pilling is a function of fiber content, spinning method, twist, contiguous staple length, and fabric construction. Single ply yarns or using fibers like merino wool are known to pill more due to the fact that in the former, the single ply is not tight enough to securely retain all the fibers under abrasion, and the merino wool's short staple length allows the ends of the fibers to pop out of the twist more easily. Yarns combining synthetic and natural fibers inherit the properties of each parent, according to the proportional composition. Synthetics are added to lower cost, increase durability, add unusual color or visual effects, provide machine washability and stain resistance, reduce heat retention, or lighten garment weight. == Structure ==