fash 15 textiles finishing. finishing—an overview finish—any process that is done to fiber, yarn...
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finishing—an overview
finish—any process that is done to fiber, yarn or fabric either before or after fabrication to change:
• appearance—what is seen• hand—what is felt• performance– what fabric does
all finishing processes add to cost
fabric production—fiber processing
EXAMPLE:cotton polyester blend
•cotton fibers are processed separately from polyester fibers
• polyester produced as filament tow, crimped, cut or broken into staple fibers
• cotton needs considerably more processing—grown, picked, ginned, baled, shipped, grade assessed
fabric production—yarn processing
fibers are aligned, blended & twisted•cotton & polyester bales are opened •fibers are loosened and aligned•cotton bales blended to ensure fabric performance and quality•fibers often combined in drawing or roving stage•once fibers are blended, appropriate amount of twist is added to yarns•spun yarns wound on bobbins•shipped to mill for fabric production
fabric production—yarn preparation
involves several steps•sizing (mixture of natural starches & synthetic resins) coats warp yarns to reduce abrasion & tension of weaving•fabrication follows sizing—fabric woven, knitted or created in some other manner•preparation & pretreatment of fabric next—
• improving absorbency• reducing shrinkage• removing impurities• whitening
fabric production—fabric preparation
handling —refers to the physical form of fabric during finishing—width, length & fabrication
singeing—burns any fiber ends projecting from surface of fabric
desizing—sizing added to warp yarn removed
cleaning—warp sizing, dirt & oil are removed
scouring—general term referring to removal of foreign matter or soil from fabric prior to finishing or dyeing
fabric production—fabric preparation
bio-polishing—use of cellulase enzyme treatment to remove fuzz from spun cellulosic yarns
bleaching—process of whitening fibers, yarns, or fabrics by removing irregular natural color
optical brighteners—also used to whiten off-white fabrics—not bleaches; mask yellow by absorbing light
mercerization—treating cellulosic fabric or yarn with an alkali to increase luster, strength, and affinity for dyes
• tension• slack
fabric production—fabric preparation
ammoniating finish—less expensive alternative to mercerization used on cotton & rayon; treated with weak ammonium solution at high temps
coloration—color normally added at this stage
special purpose finishes—usually follow dyeing to avoid interference with fiber dye absorption; wrinkle resistance, soil-release, & fabric softening appropriate for cotton/poly blend
drying—especially frequent with cellulosics to minimize mildew & weight
fabric production—fabric preparation
tentering—supplies lengthwise & crosswise tension to fabric while it dries to produce uniform length & width
fabric production—fabric preparation
tentering—supplies lengthwise & crosswise tension to fabric while it dries to produce uniform length & width
loop drying—drying fabrics with soft finish (towels & knits) without tension on loop frame
heat setting—fabric placed on tenter frame and passed through oven to set and special purpose finishes
calendaring—mechanical finish performed by series of rollers between which fabric passes; simple, friction, moire, schreiner, embossinghttp://www.youtube.com/watch?v=0jjHPHj9EJA
fabric production—reworking
includes inspecting fabric for defects & flaws
fabric inspection—done by moving fabrics over an inverted frame in good light
repairing—corrects flaws marked by inspectors when economically feasible
• Broken yarns clipped• Snagged yarns worked into fabric• Defects marked so adjustments can be made
finishing steps for wool
crabbing—finishing process used to set wool fabrics; immersed in hot water then cold water & passed through rollers
decating—produces a smooth, wrinkle-free finish and lofty hand on woolen & worsted fabrics; comparable to steam ironing
carbonizing—treatment of wool yarns or fabrics with sulfuric acid; destroys plant matter and allows for more level dyeing
pressing—woolen fabric placed between metal plates that steam & press
environmental concerns & sustainability
finishing transforms a harsh, unattractive fabric into an attractive one—environmentally the impact can be significant
uses significant quantities of energy & water, potentially hazardous chemicals
systems are in place for air-pollution control, pollution prevention, & pollution reduction
• less hazardous chemicals used • reclaim & reuse of chemicals• excess use of chemicals, water & energy
being regulated