INTRODUCTORY TEXTILE SCIENCE EXAM 2 STUDY GUIDE Ch 13 20 Test at 9 05 am Friday March 23 2011 Chapter 13 Yarn Structures What is the difference between staple spun yarns and filament yarns Staple spun made from staple length fibers Must be held together by some means to form yarn usually twisting Filament long continuous strands of fibers made from manufactured fibers or silk filament What is the difference between monofilament and multifilament yarns Monofilament single strand ex Fishing line artificial hair Multifilament many fine filament yarns joined together Know what an S and a Z twist are What is a plied yarn If the original single yarns are spun Z what direction does the ply twist need to be OPPOSITE S If you take two or more plied yarns and ply them together again what is the new yarn structure called CORD What would the final plying direction be OPPOSITE AGAIN Z Know the difference between simple plain yarns and fancy novelty yarns Simple yarns Yarns that are fairly smooth and uniform along their length Simple single monofilament yarn a simple yarn made of one long filament nylon sewing thread Simple single yarn a simple yarn made of long filaments Simple single staple yarn a simple yarn made of short staple fibers twisted together Fancy Yarns Yarns that have unlike parts and that are irregular at regular intervals may be single plied or cord may be spun filament or textured or any combination classified according to their number of parts and named for the effect that dominates the fabric Know the difference between these novelty yarns corkscrew boucle chenille slub Boucle loop or curl yarns has closed loops at regular intervals Corkscrew spiral yarns have two plies one soft heavy the other fine Slub either ply or single yarns of staple fibers thick and thin in places Chanille Made by cutting a specially woven ladderlike fabric into warpwise strips What is the difference between covered and corespun yarns Covered yarn Core of one yarn is completely covered with another YARN Corespun yarns Center core is covered with a wrapping of FIBER Know the effect of the amount of twist on yarn low high crepe Extremely high twist crepe wrinkle free textured High Twist appearance firmer smaller smoother behavior resilient against wrinkles durability resistant soil abrasion snagging Low Twist appearance soft more texture behavior fibers loose durability less abrasion resistance Know the difference between the direct and indirect methods of measuring the size of yarn What is denier What is a yarn count Direct Measuring BIG BIG YARN for FILAMENT YARNS Tex weight in grams of 1000 meters of yarn Denier weight in grams of 9000 meters of a yarn A 2 denier yarn is a yarn in which 9 000 meters if weighed would equal 2 grams Indirect methods BIG SMALL YARN for STAPLE YARNS based on a fixed weight of yarn how much length to get that weight How many yards can be spun from a given weight of fiber Count number of hanks spun from 1 lb of fiber Cotton 840 yard hank Chapter 14 Manufacturing Yarns What is a texturized filament yarn How is it done What are the advantages of texturized yarns Filament Yarn The fiber produced may be used as a yarn with no further processing Textiles will be smooth slippery and shiny They might be textured to add bulk see following slides They might be cut into staple lengths sometimes blended with other fibers and spun Texturizing Filament Yarns Adds bulk resiliency softness and provides stretch Less expensive than cutting and spinning May be done by one of two processes Mechanical Thermochemical Mechanical Filaments are tangled into loops ex Air jet method Slack filaments formed into loops by jets of air Thermochemical Filaments are stretched twisted and heated wavy shape remains after filaments cool What is the difference between carding and combing fibers Which is more expensive Why Carding drums with fine bent wires separate and align fibers can also blend different fibers like cotton and cut polyester most common process used in the industry Combing A comb arranged the fibers into a parallel alignment removes short fibers and small tangles final yarn will be smoother stronger and more lustrous MORE EXPENSIVE because it requires an extra step of removing shorter fibers What is drawing when it refers to preparation of staple fibers for spinning Drawing the carded or combed fibers are put through rollers forms a long smooth strand of fibers called a sliver further drawing produces a roving ready to be spun What is the difference between the woolen and worsted system for preparing and spinning wool What would be appropriate end uses for each of these types Woolen wool is carded fuzzy sweater Worsted wool is combed men s suit What is the difference between ring spinning and open end spinning What are the advantages of each Ring Spinning Roving is fed down drawn out thinner through the ring and onto the bobbin Going around the bobbin twists the roving into yarn Pros fine smooth yarn high quality stronger better hand Cons slower more expensive Open Ended spinning Fibers separated into thin stream by rotary beater Moved by air enter rotor Drawn off to become attached to open end of already formed yarn Pros faster less expensive Cons rougher weaker coarser lower quality hand good for towels denim What are slit film yarns Slit films are made by cutting film into narrow ribbon like sections Chapter 15 Fabrics and Related Structures How is the weight of fabric determined What constitutes light top weight medium bottom weight and heavy weight fabrics Expressed as ounces per square yard 1 ounce very sheer 2 4 ounces top weight shirts blouses 5 7 ounces bottom weight skirts slacks 9 11 ounces heavyweight men s jeans Fabric weight ounces per square yard direct measurement higher the the heavier the fabric a function of the yarn used top weight 2 4 ounces is called light weight and used for blouses sheer curtains Bottom weight 9 11 ounces jeans pants Heavyweight 14 ounces upholstery Chapter 16 Woven Fabrics What is a loom What does it do What are the warp and filling weft yarns Why do the warp yarns need to be smooth and strong Loom device on which woven fabrics are produced Warp The yarns that are put onto the loom Usually smooth and strong Must withstand high tension and abrasion your samples have the warp on the longest side Weft filling The yarns that are interlaced with the warp Can be soft or textured What is a fabric thread count How is it measured What is a balanced weave