Fabric Science - Chapter 4: Yarns and Sewing Threads

air-jet method

jet of high-velocity air is directed at a multifilament yarn, which separatesthe fibers, forcing some filaments to form loops and turns; result is a bulkier, less lustrous yarn

bare elastic yarn

usually composed of monofilament spandex fiber, used in power-stretch fabrics, provide softer and more gentle shape control than covered yarns

blended yarn

yarn made of two or more fiber types, spun yarns most widely used, usually done to combine desirable properties of different fibers, longer fibers tend to travel toward the center and shorter towards the outside

bulk-textured yarn

high bulk w low or minimal stretch. method for producing is stuffer-box method, which produces an increase in bulk from 200 to 300 percent and can be found in yarns made for carpets, filaments compressed into heated chamber and heat-set w wavy, random crimp --- relatively bulky, some degree of stretch, torque free

carded

all staple fibers have to be carded to help clean and disentangle them, is formed into a thick rope of loose fiber called sliver

chenille yarn

yarns that have a soft pile protruding from their surface, soft, supple, very flexible

combed

finer fabrics, carded fiber goes to combing unit, which further cleans the fibers and puts them in a parallel position, removing short fibers, has longer fibers, more parallel position, more uniform length, fewer impurities, and more uniformity

core-spun yarn

have a central filament core of spandex with staple fiber that has been spun around the core, the hand texture andappearance are identical to owhat the spun yarn would be without the core center, used in comfort stretch fabrics

cotton count system

for cotton and cotton blends, expressed by yarn size and yarn ply, specified as c.c. or Ne

covered elastic yarn

monofilaments wrapped or covered w a spun for filament yarn to hide the elastomeric yarn, tend to be thick and heavy, used in power-stretch fabrics, provide firmer and more powerful shape control than bare elastic yarns

crepe twist

some filament yarns purposely made with high twist to produce a pebbly, harsh surface effect - crepe filament yarns

decitex system

used to measure the weight in grams of 10000meters of length, often used when referring to a very low tex number

denier

system used for filament fibers and filament yarns, is a direct system because higher denier numbers designate heavier (thicker) yarn

false-twist method

most widely used technique for producing textured yarns in finer deniers; yarns are twister, heat-set, and untwisted in one operation

filament yarn

composed of continuous strands of fiber that may be miles long, produced directly from spinnerette or silk cocoon

gear crimping

passing filament yarn through series of heated rollers of gears that deform the filaments

growth

unrecovered stretch, can be kept to very low tolerable minimums

hard twist

spun yarns w relatively high tpi, causes them to be smoother, firmer, kinkier, and stronger

high-bulk (hi-bulk, turbo-bulk) yarn

acrylic spun yarns that are specially processed to yield lofty, bulky, and soft yarns without stretch

knife-edge method

process consists of passing filaments over a heated roll then pulling them over a sharp edge at an acute angle

knife-deknit method

way of producing a bulky yarn that has more stretch than yarn produced using stuffer-box or air-jet methods, filaments are knit into a narrow-diameter tubular form then rolled up, heat-set and unraveled

lea

linen yarns expressed by this term or NeL, used for flax jute hemp and ramie, almost never plied by the fiber length is so long, considered single yarns

line linen

composed of long fibers averaging 15 in, smooth and fine

metallic yarn

fine strip of metallic fiber, flat and ribbonlike, mostly used for decorat\ive rather than functional purposes

metric yarn count

system that expresses the number of kilometers of yarn per kilogram of weight, can be indicated by Nm except for cotton which is Ne

microfibers

fine fibers made of microfilaments, also known as microdenier

microfilament

fibers produced in diameters finer than silk, such as nylon, polyester, lyocell

mixture

fabric composed of two or more different types of yarn, also used to lower the cost of certain fabrics or add strength, sometimes referred to as a combination fabric

monofilaments

filament yarn composed of one single filament stiffer and less flexible than multifilament yarn of the same diameter

multifilaments

filament yarn composed of many filaments

novelty yarn

yarns not of uniform thickness throughout their length but have deliberate irregularities on their surfaces

open-end (oe) spinning

higher rates of production than ring spinning, saves space, power, and labor reqs - carded sliver fed to oe spinning unit, which separates fibers, twists them together, and wides them onto spools or cones

ply

two or more single yarns twisted together to form one new yarn

ring spinning

fibers are carded to bring them into a more parallel position and bundled into a loosely formed robe about one inch in diameter, known as sliver

ring-spun yarn

conventionally spun yarn, produces yarns with the softest hand available but costly

run

woolen and woolen blend yarns designated by this term, rarely plied and single yarns unless otherwise indicated

set-textured

textured yarns that undergo an additional heat-setting step in the texturizing process to set the yarn and eliminate or greatly minimize stretch

sewing thread

special kinds of yarns engineered and designed to pass through a sewing machine rapidly, to form a stitch efficiently, and to function while in a sewn product without breaking or becoming distorted

single

single spun yarn

soft twist

spun yarns with relatively low twist, softer, fluffier, more flexible, not as strong, knitting yarns

spun yarn

composed of relatively short lengths of fiber twister or spun so that they hold together

stretch-textured yarn

made primarily from nylon and used extensively in leotards, stretch leggings, pantyhose, and similar items. these yarns can be stretched from 30 to 50 percent of their relaxed length

tex system

direct system, intended to replace all existing systems with a single system for designating yarn sizes, uses grams per 1000 meters

textured yarn

when yarn is modified and takes on an entirely new surface or texture, most widely used of the comfort stretch yarns

thread size

size of thread - heavyweight thread should be used for heavyweight fabrics, lightweight for lightweight fabrics, and extra fine for sheer or fabrics made of microdenier yarns

tow linen

composed of short fibers and is irregular and rather coarse in texture, used for coarses types of linen fabrics

turns-per-inch or tpi

amount of twist in a yarn in terms of inches, important bearing on appearance and durability of the yarn and the fabric that will be made from it

turns-per-meter or tpm

amount of twist in yarn in terms of meters

woolen

made of carded yarns, fuzzier, more uneven diameter, bulkier, wider range of fiber length

worsted

made of combed yarns, smooth w little fuzz, has even diameter, more tightly twisted and firmer

worsted count system

worsted, worsted blends, acrylic fibers designated by w.c. or NeK, indicated in the reverse order from the cotton count system, ply/yarn size

yarn count

yarn count number is inversely proportional to weight, indirect

yarn number or size

xpresses relationship bt unit of length and weight and close relationship to diameter or thickness

yarn numbering system

used to express relationship bt unit length and weight of yarns, either direct or indirect