Textiles

B

Spinning

Only twisting is required to process filament fiber into yarn, but staple fibers must be carded to combine the fibers into a continuous ropelike form, combed to straighten the long fibers, and drawn out into continuous strands, which are then twisted to the desired degree. In general, the amount of twist given the yarns determines various characteristics. Light twisting yields soft-surfaced fabrics, whereas hard-twisted yarns produce hard-surfaced fabrics, which provide resistance to abrasion and are less inclined to retain dirt and wrinkles. Fabrics made from hard-twisted yarns, however, are subject to greater shrinkage. Hard-twisted yarns are used in producing hosiery and crepes.

C

Weaving

Two sets of yarns, called the warp and the woof (more commonly filling, or weft) are used in weaving, which is carried out on a mechanism known as a loom. Warp yarns run along the length of the loom; filling yarns run across it. The warp is wound on huge reels, called beams or creels, that are placed at the feet of the loom, and the warp yarns are threaded through the loom to form a series of parallel threads. The filling is fed from the side of the loom by bobbins, which are changed either automatically or manually when the yarn runs out. The loom shuttle carries the filling yarns across the loom, interlacing them at right angles with the warp yarns. Different patterns and textures are achieved by varying the number of warp yarns and by altering the sequence in which they are raised or lowered. A temporary protective coating known as sizing protects the warp yarns against damage during the weaving operation.

D

Knitting Machines

Knitting, which originated with the knotting of fishnets and snares by ancient peoples, is the craft of forming a fabric by the interlocking of yarn in a series of connected loops by means of hand or mechanized needles. The craft of knitting was introduced into continental Europe by the Arabs in the 5th century, and flourished in England and Scotland in the 14th and 15th centuries. The Scots have claimed both its invention and its introduction into France.

All knitting was done by hand until 1589, when the English clergyman William Lee invented a machine that could knit stockings. Queen Elizabeth I of England refused Lee a patent for his machine, considering the new invention a threat to many of the hand knitters in the country. The machine, however, was used in other countries, and paved the way for further improvements. The first addition came in 1758, when a British cotton spinner, Jedediah Strutt, invented an attachment to the stocking frame that could produce ribbed fabric. In the early 19th century the British engineer Marc Isambard Brunel invented a circular knitting frame, to which he gave the name tricoteur. The knitting of heavier yarns became possible when another British inventor, Matthew Townsend, introduced the latch needle, a needle having a latch-closed hook at one end, which he patented in 1858. In 1864 William Cotton, also in Britain, introduced an improvement in power machines that became known as Cotton’s system. The improved machine was capable of shaping the heels and toes of hosiery, and it laid the foundation for the modern full-fashioned machines. Automatic knitting machines were first introduced in 1889. See Sewing Machine.

---

---

E

Dyeing and Printing

Textiles may be dyed in a number of ways: The fabrics can be dyed after weaving or knitting is completed (piece-dyed), the loose fibers can be dyed in a vat (stock-dyed), or the yarn or filament can be dyed before weaving or knitting is begun (yarn-dyed). Synthetic yarns can also be precolored by incorporating color pigments in the spinning solution before the filaments are extruded through the spinneret (solution- or dope-dyed).

The principal method of printing designs on textiles is intaglio roller printing. In this process, the design is etched on copper rolls, a separate roll for each color in the design, the depressions are filled with printing paste, and the fabric then passes through the rolls. Another method of printing fabrics is relief roller printing. In this process, the design is raised away from the surface of the roll, and the raised portions are covered with ink. This is also called surface, peg, block, or kiss printing. Screen printing is accomplished with a design stenciled on a flat or roller screen. The screen is placed over the fabric and color is applied by squeegeeing it through the openings in the stencil. Hand-screen printing is being replaced by automatic machines. See Printing Techniques.

F

Other Finishing Processes

In addition to coloring and printing, other finishes applied to the fabric to improve its appearance and service include treatment to promote crease resistance in such textiles as cotton, linen, and spun rayons, which do not have the elasticity of silk and wool. The latest developments in crease-resistant finishes are the so-called durable press, or permanent press, finishes. In addition to wrinkle resistance, these finishes impart permanent creases where desired, as in slacks. Resistance to shrinking, staining, and soiling also may be provided by various chemical treatments. Other finishing processes protect against slipping of threads or damage by mildew, moths, or flame.

	More from Encarta
	•  Presidential Myths Quiz •  Coffee break: Recharge your brain