Tài liệu Understanding textiles for a merchandiser by dr shah alimuzzaman belal ctext fti associate professor head of the fabric manufacturing engineering proctor bangladesh university of textiles

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P##f#SM #nING TW lk1% FQR No R TeytiIe fibres;Yarn and b'zrn m anufacturing; W eaving technology;Fabricstructure and design;SpeciaIw oven fabric production; W eftand w arp knitting technology;Knitted fabric design;Specialknitfabric production; Sw eaterknitting; Dyeing,printing and finishing. Engr.ShahAlimuzzaman BelalG ext.ATI.(U.K.) Assistant Professor College ofTextile Engineering and Technology Dhaka,Bangladesh Published by BM N3foundation Dhaka,Bangladesh. TABLE O FCONTENTS Contents Introduction to textiles Flow chartoftextile processing Textile fibres Yarn and yarn m anufaeturing Propertiesoftextile fibres Prim ary propertiesoftextilefibres Secondary propertiesoftextilefibres Classification oftextile fibres Fibre identification Burning test Lightmicroscopytest Chemicalsolubility test Typesoffibres Classification ofyarn Typesofcottonyarn Blowroom section ProcessIayoutoftheyarn m anufacturing system w ith a modern blowroom Iine Carding section Doubling and draw ing Com bing section SimplexorRovingfram e Cotton spinningsystem Spinning machine Autoconer Yarn conditioningand packing Yarn num bering system Definition Typesofyarn count Calculationsconcerning count Form ulaeforcountconversion Countcalculation and denotion forpI y yarn Length calculation ofacone ofsew ing thread Fanc# Yarns Fancyyarn Coloureffects Structure effects Lustre effects Page no. 002 003 004 004 004 006 011 O12 012 014 018 021 O21 021 024 025 028 030 030 032 034 035 36 039 040 041 041 041 044 046 O47 050 051 051 051 051 052 Fabric and Fabric m anufacturing W oven fabrics and W eaving technology Typesoffabric Fabricclassifitationataglanee W oven fabries Proeessflow to manufaduringwoven fabric W eavingpreparation W inding W indingprocess Tensiondevice Typesofpackages Pirnwinding W inding machine Precisionwinding Problem W arp preparation W arping DirectorHighspeedwarping IndirectorSectionwarping W arping machine SizingorSlashing Sizing machine Drawing-in andTying-in Fundamentalsofweaving W eaving principle Basicw eavingm otions W arp Iet-off W arpshedding W eftinsertionorpicking Yarnaccumulatorsorfeeders Beat-up Take-up Auxiliaryweavingmotions Fabricwidth W eavingmachine orLoom Shuttleweavingmachines Shuttlelessweaving machines Projectileweavingmachine Rapierweaving machine Airjetweavingmachine Water-jetweavingmachine M ultiphaseweaving machine Fabricsel vages GreyfabricinspectionIines 053 053 055 056 057 057 057 058 059 063 069 071 072 072 073 074 074 076 077 079 083 086 089 093 093 095 095 096 096 098 100 102 103 103 105 106 107 108 110 111 113 114 115 117 Fabric structure and design lntrodurtiontofabricstruetureanddesign W oven fabricspecification Fabricweightcalculation Yarn consumption calculation Partsofa complete desi gn Drafting System orclassi fication ofdrafting Basicweavesofwovenfabric Plain weave M ain featuresofplainweave Classification ofplain c10th Derivativesofplainweave Rib weave M attweave Ornam entation ofplain (10th Twillw eave Classification oftwillweave Derivativesoftwillweave Zig-zagtwillweave Herringbonetwillweave Diamond design Diaperdesign Brokentwillweave Re-arranged twillweave Stepped twillweave Elongated twillweave Com binedtwillweave Shadedtwillweave Advantagesand disadvantagesoftwill Satin weave Classificationofsatin weave Construdion principle ofsatin weave Derivativesofsatin weave Crepeweaves Corkscrew weaves Shaded weaves Fancy design orstructureoffabrits Huckabackweaves M ockIeno weaves Honeycomb weave Distorted thread e/ect Cord weave Spongeweave 118 119 121 121 123 125 129 131 134 135 135 136 137 138 141 144 146 147 153 154 159 162 165 167 168 173 175 179 183 186 187 188 189 194 195 201 202 205 205 209 211 217 220 227 Colourand weave effects Sim ple colourand weave effects Com pound colourand weave effects Figuringw ith extra threads Com pound fabrics Tubularc10th Double width c10th M ulti-plyfabrics Stitched double cloths Classification ofdouble c10th Selection ofsuitable stitching positions Construction principle Selfsti tchdouble c10th W added double c10th Centre stitch double c10th Fabric used in apparelsector Fabric based on plain weave Fabric based ontwillweave Othercom mercialfabrics Fabricconstruction orspecification spetialfabrit produd ion 229 231 235 238 241 241 242 242 244 244 247 248 248 251 253 256 256 261 263 265 267 Braid fabrics 268 M anufacturing principle 269 End uses 270 M ulticom ponentfabrics 271 Bonded fabrics 27 1 Lam inated fabrics 272 Quilted fabrics 273 Leno orGauze fabrics 277 W eaving principle and end uses 278 Lappetand Sw ivelfabrics 280 Lappetw eaving principle 280 Featuresofsw ivelw eave 281 Denim fabrics 283 Featuresand raw m ateriaisofdenim fabric 283 W arp preparation 285 W oven pile fabrics 288 W eftpile fabrics 288 W arp pilefabrics 292 The w ire m ethod 292 The doubIe-cloth orface-to-face m ethod 295 The slacktension pile orterryw eave 305 Flocked fabrics 313 Tufling:Tufted carpet 315 Knitted fabricsand Knitting technology Introductionandhistoricalbackgroundofknitting Generalterm srelated to knitting technology M echanicalprinciplesofknittingtechnology Basicelem entsofknitting The need1es The cam s The sinkers M ethodsofyarn feeding M ethodsofform ingyarn into needle Ioops Stitch form ation on bearded needles Loop formation on Iatch needles Knitting action ofcom pound needles W eftknitting m achines M ain featuresofa knitting m achine Classification ofweftkni tting m achines Flatknitting m achine Circularkni tting m achine Fabric m achine Garment-length m achines Single-jerseycircularknittingmachine 322 326 337 337 337 341 344 345 346 347 349 351 354 354 354 356 358 361 362 363 Rib circularknitting m achine Interlock circularknitting m achine Links-linksorPurlknitting m achine Basicw eftknitted structures The plain knitstructure orplain fabric The rib structure orrib fabric The purlknitstructure orpurlfabric The interlockstructure orinterlock fabric Com parison between basicstructures 369 377 380 383 383 385 389 392 394 Identificationofsingleand doublejersey 395 Basic Ioop orstitch types The held loop Thefloatstitch orIoop Thetuck Ioop orstitch The drop orpress-offstitch Designsofw eftknitted fabrics 396 396 398 403 411 413 Ornamentationofsingle-jerseyfabric Single-jerseyderivatives Double-jerseyderivativesbasedon rib 413 414 421 Derivativesofinterlockstructure 427 W eftknittedjacquarddesign Single-jerseyjacquard design Double-jerseyjacquarddesign 437 437 441 t.,,; yy l )) %) lt ' t ) ( t y . Sweaterknitting Featuresofthesweaterknittingmachine 446 447 The manualsweaterknitting machine Productionofdifferentfabricsonsweater kni tting machine 448 . 4s3 t l @ <41 ' t è 7 ' Theset-up 453 ) Tubularfabric Singlebed fabric Ribfabrics Needle-bed racking 454 455 456 459 Stitchorlooptransferinweftknitting 461 The welt 477 Garmentpanelseparation 480 Shaping during knitting 482 Shapeformation 483 Shaping orfashioningfrequenciescalculation 487 Linking operation 491 Knitted fabricfaults 494 Calculation relatedtoweftknitting 501 Knittingspeed and machinerpm 502 Speedfactororpedormance number 503 Production calculation 504 W eightperunitareaand coverfactor 5O9 Relationbeto yarn count& m achinegauge 511 Relationbetween yarn countand GSM 512 W arp knitting principle 514 lntroduction to warp knitted fabrics 514 The guides 515 The pattern mechanism 517 Chain finks 519 The warp beams 521 Lapping diagramsand chain notations 522 Basicstitchesin warp knitting 523 W arp knitting maehinery 531 Tricotwarp knitting machine 531 Raschelwarp kni tting machine 538 Two fully threaded guide barstructuresorfabrics 546 Spetialknitfabricproduction 553 Knitted pile fabrics 553 Fleece knitfabric 553 High pile knitfabricsorsliverknitfabrics 555 Plush fabricsorknitted terry fabrics 557 The crochetwarp knittingm achine 559 The straightbarframe 563 . è . j @ 'i ) i r ' Netting ornetfabrics Lace fabrics Nonw oven fabrics Raw m aterials W eb form ation W eb bonding Finishing Characteristics and uses ofnonw oven fabrics Specialty nonw oven products Textile dyeing,printing Preparatory processorpre-dyeing treatm ents and finishing Singeing Desizing and Scouring Bleaching M ercerizing Heatsetting Elasticfabric W ashing Drying Dyeing Preparation and dyeing m achinery Autoclaves W inch dyeing m achine Jiggers Dyestuffs Printing Printing principle Printing processes Functionalfinishing M echanicalfinishing treatm ents Chem icalfinishing treatm ents 568 570 579 579 580 583 588 589 590 591 592 593 594 595 596 598 599 600 605 612 613 615 619 621 622 623 624 627 630 631 640 Acknow ledgem ents Gratefulacknowledgements are made to m any of my friends, colleagues and dear students who have relentlessly encouraged me to writethiskind ofa bookand read differentchapterof thisbook,given encouragementand very helpfulcriticism . Specially,Iwould Iike to show a huge appreciation to my beloved wife Sumona and m y Iittle girlsHafsa,Sumaia and Eusha.W i thout theirsupportand patience lwould never have been abletofinish thiswork. 02 INTRODUC ION TO TEXTILES The word ''textile' 'originally applied only to woven fabrics, now generally applied to fibres, yarns,orfabrics or products m ade of fibres, yarns or fabrics.The term textile originates from the Iatin verb texere - to weave - but, asthe Textile Institute'sTerm sand Defini tions Glossary explains, it is now /'a generalterm applied to any manufacture from fibres, filam ents or yarns characterized by flexibility, fineness and high ratio of Iength to thickness'' Textiles,especially fabric isthe fundam entalcom ponentofa readym ade garm ent, because it is the basic raw m aterialof a garm ent. So it is im portant to know the m anufacturing sequence offabric from fibre.The quality product isthe m ain goalat presenttim e, W ithout knowledge ofTextile manufacturing i.e.fibre,yarn and fabrics it is im possible to m aintain the qualityofagarment.Before elaborating on whole process ofgreyfabric m anufacturing let us look on what is textile fibre, yarn and fabric and what are the processflow chart of Textile M anufacturing can be described. . Textile: A term originally appbied only to w oven fabrics, but the term s textile and the plural textiles are now also applied to fibres,filaments and yarns, naturaland m anufactured, and m ostproductsforw hich these are a principalraw m ateriai. * Textile Fibre: Any substance, naturalor manufactured, with a high Iength to width ratio and w ith suitable characteristicsforbeing processed into fabric;the smallestcom ponent, hairIike in nature,thatcan be separated from a fabric. @ Yarn: An assem blage of fibres that is twisted or laid together so as to form a continuous strand that can be m ade into a textile fabric. So a yarn is a strand of naturalor m an m adefibresorfilamentsthathave been twisted orgrouped togetherforuse in w eaving, knitting, or other m ethods of constructing textile fabrics. The type of yarn to be manufactured willdepend on the fibres selected;the texture, or hand,ofthe fabric to be m ade;and qualities such asw arm th,resiliency, softness,and durability required in thefabric'send uses. q' @ Fabrk: Fabricisa ffexible pdanarsubstance construded from solutions,fibres,yarns,orfabrics, in any combination.Textile fabrics can be produced directqy from webs offibres by bonding,fusing orinterlocking to make non-woven fabrics and felts,buttheirphysical properties tend to restricttheir potentialend-usage.The mechanicalmanipulation of yarn into fabricisthe mostversatile method ofmanufacturingtextile fabricsfora wide rangeofend-uses. FIoW chartoftextileprocessing: lnput/Raw materials Textile Fibres Protessingsteps Output Yarn Manufacturing Yarn (SpinningMiII) Yarn FabricManufacturing Grey Fabrics (Weaving/KnittingIndustry) Grey Fabrics W etProcessing Fini shed Fabrics (Dyeing,Printing&FinishingIndustry) Finished Fabrics GarmentManufacturing (GarmentIndustry) Garments 04 TEXTILE FIBRES Any substance,naturalorm anufactured,w ith a high Iength to w idth ratio and with suitable characteristics forbeing processed into fabric;the sm allest com ponent,hairIike in nature, thatcan be separated from a fabric. Properties ofTextile Fibres: Prim ary properties oftextile fibres: High Iength to w idth ratio Tenacity Flexibility Spinningquality(Cohesiveness) Uniform ity Setondary properties oftextile fibres: Physicalshape Elastic recovery and elongation Resiliency Flam m ability and othertherm al reactions Density Lusture Colour M oisture regain Prim ary propertiesoftextile fibres: High Iength-to-w idth ratio: ; Fibrous materialsmustpossessadequate staple (fibre Iength)and the Iength must be ' considerably greater than the diam eter.The length is a vew im portant fibre property. p to severalcentim eters Iong. t Naturalfibres,exceptforsilk,are m ostly som e m illimeters u' (- ttSynthetic fibres are actually filaments (indefini te Iength)or are chopped into (shorter) ( :')j :staple fibres,w hich can,in theirturn,be spun. E.(? ( C J L . j-k .l h.' . yj . ) l L ï '. : j.. ... . 06 --wjujjje Flexibility is the property of bending without breaking that is the third necessaw characteristicoftextile fibre.In orderto form yarnsorfabricsthatcan be creased,thathave the quality of drapability and the ability to m ove with the body and that perm it general freedom of m ovem ent, the fibres m ust be bendable, pliable or flexible. The degreq of flexibility determ ines the ease with which fibres, yarns and fabrics will bend and is im portantin fabricdurability and generalperform ance. SpinninzqualiW (fnh- WR*--Q): This charaderistic refers to the ability ofthe fibre to stick together in yarn m anufaduring processes. Cohesiveness indicates that fibres tend to hold together during yarn m anufacturing asa resultofthe longitudinalcontourofthe fibre orthe cross-section shape thatenablesthe fibreto fittogetherand entangle sufficiently to adhere to one another- Un' i* : To m inim ize the irregularity in the finalyarn,it is im portant that the'fibres be som ew hat sim ilarin length and width i.e.be uniform.The inherentvariabilit' y in the naturaltibre can be averaged outby blending naturalfibresfrom m any different batchesin orderto produce yarn thatare uniform . W onzaa - 'e oftoe lle & -'': * 0 10 1shaN (sne*n* .* a 'ap- o- ): The fibre shapes i.e.the sudace struclure is im portantforthe fibre behaviourin a yarn and in a fabric.A rough scaly sudace of w oolfibres,for exam ple,ihfluences the feltingrand shrinkage properties ofwoolfabrics.The scales enable fibresto grip one anotherw he' na yarn isspun. The smooth,glassysudace ofa fibre such asthe nylon fibre,affed sthe lustre ofthe fibre-A sm ooth sudace will not cling to dirt so readily. The cross-sectional shape of a fibre influencesthe behaviourofthefabric.A circularornear-circularcross-section (wool)gives an attradiveorcomfortablefeelascomparedto aflat,ribbon-likecross-section lèottonlCircularfibresoften have a poorercovering-powerthan the flatterortriangularones:A flat ortriangularcross-section givesmore Iustre.Serrated orindentedcross-sectio/s(viscose) give bettercolourabsorption as a result ofthe Iargerarea.M ore colour is also needed in the case offine filam ents.The latteralso give a softerhandle orfeel. : Elao -c and - : Afibre,whichissubjededtoaforce,willstretchtoacertaindegree-Thisstretchingcan alsobe expressed asapercentage ofthe originalfibre lenglh,which isthe elongation-The elongatio:of 97 a fibre m ay be m easured atany specified load oras the elongation reached when the fibre breaks. Whenafibreissubjeded toasmallforce(orstretchedtoasmalldegree),itmayexhibit almost pedect elasticity.Elasticity is the property ofa fibre to recover its originallength afterstretching caused by a Ioad. The term breaking elongation refers to the amount of stretch that occurs to the point where the fibre breaks. Elastic Recovery designates the percentage of return from elongation or stretch toward the originalIength or m easurement.Ifa fibre returns to its originallength from a specified am ount of attenuation, it is said to have 100% elastic recovew atX% elongation. Resilienty: lt is the ability of a fibre to return to shape following compression, bending or similar deform ation.It is im portant in determ ining the crease recovery ofa fibre orfabric,and it plays a significant role in the rapidity with which flattened carpet pile willregain itsshape and restore itsappearance. Resilience is the property of a fibre which enables i t to recover from a certain Ioad or stretched position and flexibility is that property to resist repeated bending and folding.A supple fibre has a low resilience and iseasily com pressible.A stifffibre hasa high resilience and cannotbe easily com pressed. Flam m ability and othertherm alread ions: Burning characteristics of the fibres are im portant in determ ining care and use,and they serve as helpful guidelines in the fibre identification. Federal Iegislation on textile inflam m abili ty is an im portant consum er issue and a variety of types of textile end-use productsmustmeetaspecified resistancetoflames. AIIfibresare affected in one-w ay oranotheras they are heated.Som e,Iike wool,begin to decom pose before melting;others,Iike polyethylene oracetate willsoften and m eltbefore decom posi tion sets in.The behaviouroffibres on heating and theirigni tion propertiesare of great practicalim portance.Indeed,fabrics should withstand the temperatures used in ironing,laundering (with waterorsolvent)etc.Since syntheticfibresare thermoplastic substances(i.e.theywillsoftenastheyare heated),thissofteningwillIargelydetermine theirpracticalusefulness. In the presence ofair,m ostfibreswillburn.ln thiscontext,theterm LOIisused.Itstandsfor Lim iting Oxygen Index.The higherthe value ofLOI,the more difficulta substance willignite since LOIisa m easure ofthe am ountofoxygen w hich hasto be presentin the airto leta substance(continueto)burn.Onaverage,moststlbstanceshaveanLOIofabout20.Effortsare m ade to reducetheflamm ability oftextile m aterialsin orderto Iim itaccidents.These effortsare 05 The staple Iength ofnaturalfibres isnotan easy property to define because the fibre Iength can vary overa greatarea.A statisticalinterpretation ofthe data obtained on fibre length in a Iaboratory,makesitpossibleto determine the staple Iength (an average length).ln order forafibre to be spinnable,i.e.to be twistable,and therefore offersufficientcohesion to the whole,a fibre m ust at least have a Iength of5 to 15 m illim etres.Fibres which are Ionger than 150 m illim etres require specialized spinning m achines which m ake the spinning processm ore expensive. ' The mostcom mon naturalfibreshave aratio Ienglh/thicknesswhichequalsonethousand orseveralthousands(cotton:1500, 'wool:3000;flax:1200).Coarserfibressuch asjute and sisalhave ratios between 100 and 1000.W hen filam entsofm an-m ade fibres are chopped into shorterfibres,an effortis m ade to bring the ratios close to those of naturalfibres,i.e. between 1000 and 4000. T * Second necessaw property for a productto qualify fortextile fibre is adequate strength, termed as tenacity.Tenacity is defined as the tensile stress expressed as force per unit Iineardensity ofthe unstrained specim en. The strength of a fibre is generally dependent on the length of the polymer chain,the degree of orientation of these polym er chains, the strength and types of the forces of attractionbetween thepolymerchains(interpolymerforces).TheIongerapolymerchain is, the higher the degrees of orientation and crystallization and, hence, the stronger the interpolym er forces.Crystalline system s feelstiffand present less resistance to repeated bending or folding. Stronger fibres will Iead to stronger yarns under the appropriate conditionsoftw ist. The tensile strength orbreaking load iscom monly described asthe force required to reach break. lnthecaseofafibre,the strengthisdescribed astenacity(specificstressatbreak) breuking Ioad Tenacity= m ass perunit/enqttt Tenacity isexpressed in term sof (centilnewtons pertex(cN/tex orN/tex). lt is im portant to note that the fibre strength does not alw ays indicate com parable yarn or fabric strength.Fibres w ith high strength are usefulin seerand Iightw eightfabrics.Fabrics used in w ork cloths and various industrialapplications are better from high tenacity fibres. Fibre tenacity does not alw ays reflectthe actualstrength of textile yarn.Itis possible for yarns to be m ade so that fibre slippage occurs;this does not m ake optim um use of the actualfibre tenacity. 0' 8 made both in the field ofsynthesisoffibres(chemicalmodification)and,afterwards,by using substanceswhich sfow dow n orresistburning. Chem ically speaking,vegetable fibres have aim ost identicalcom posi tion, and consist of cellulose,which is a com bination ofcarbon,hydrogen and oxygen.They aIlburn aspaperor wood,ignite readily,Ieave Iittle or no ashes and release a distinctive fire smellof burnt Paper. Fibres ofanim alorigin also have a sim ilarchem icalcom position;they aIIcontain nitrogen and willtherefore noteasily burn through.They shriveland form charred ashes.They Ieave afire smellofburntfeathers. Exceptionsareweighted naturalsilk (Ieavesasheswhich keep the form ofthe yarn)and acetate w here introducing acetate groups in the pol ym er chains m akes the fibre melt before i tcan ignite. M an-m ade fibresbased on protein burn asfibresofanim alorigin.Fully syntheticfibresm elt wi thoutignition. Density: Fibreswith differentdensities butofequaldiam eterwillhave differentcovering pow erthat is the ability to cover a surface.Fabrics made w ith fibres of different densities willhave difference in fabric appearance,flexibility,airperm eabilityand cover. The density,also called volum icm assorm assdensity,isthe mass perunitvolum e and hasp asitssym bol.It is usually expressed in grams percubiccentim eter.Anotherterm is specific gravity,w hich isthe ratio ofthe m ass ofafibre m aterialand the m ass ofan equalvolum e of water(density lg/cm3).The specific gravity ofa substance vis-à-vis waterequals the numericalvalueofthe(absolute)densityofthissubstanceifitisexpresseding/cm3.Every fibre ischaracterized by its density,w hich can be m easured in variousways. M easurem entofdensity can be carried outwith a gradientcolum n,where the Iiquid in the tube hasa density which varies in height.Ifa fibre is dropped in the tube,itw illsinkto the pointatwhich the fibre density equalsthe Iiquid density,and remain suspended there. This experim ent is based on the fact that a fibre which is subm erged in a Iiquid with the sam e density willsink nor drift but float, and that the density of a Iiquid can easily be measured.Treatm ents forfinishing fibres,can influence the results.Foreign substances on orin the fibresm ustbe rem oved before doing the experim ent. 09 The Iistbelow givesan overview ofthe mostim portantfibresand theirdensities. Textile Fibres Fibredensitiesing/cm3 Commercialname Cotton Cotton Flax Jute W ool Silk Silk Silk Polyester Polyester Viscose Cupram m onium Polyurethane Polypropylene Polyethylene Polyethylene 1.55 1.54 1.50 1.50 1.30 1.33 1.60 1.32 1.22 1.38 1.53 1.53 1.15 0.90 0.92 0.95 Raw M ercerized Nyloq 6 Nylon 66 1.13 1.14 Lycra M eraklon Courlene Courlene X3 Perlon Tri-nylon Acryl 1.14- 1.17 Orlon(staple/filament) Polyvinylalcohol 1.30 Kuralon, vinal No brand Natural W eighted Tussah Kodel,vestan Teryleen, Dacron Lusture: ltrefers to the gloss,sheen orshine that a fibre has.It isthe resultofthe amountofIight reflected by afibre,and itdeterm inesthe fibre'snaturalbrightnessordullness. Colour: Naturalcolouroffibresvary from pure white to deep gray.tan orblack.M an-made fibres are usually white oroff-white asthey are produced. M oisture regain oreffed ofm oisture: AIlfibres tend to absorb m oisture when in contact w ith the atmosphere.The am ount absorbed dependson the relative hum idity ofthe air. For absorption of m oisture of a fibre, the term regain is used.This is the amount of m oisture present in a textile m aterialexpressed asthe percentage ofthe oven-dry weight (dry weight)ofthe textile.This dry mass isthe constantweightoftextile obtained after drying at a tem perature of105OC to 1100c. If B isthe dry weight and A is the conditionëd weight (the weight after being in a normalized atmosphere of 20()C and 65% rejative humidity),theregainexpressed in percentagewillbe: ). t E'1 I .1 10 MoistureRegain ïi i p :h A- B -- x100 B j' ! ; ) t Anotherrelevantterm is moisture contentand,expressed in percentage,is: M oisture content A-B x l00 A i . ; ... : ' ë:. The m oisture contentisthe m assofm oisture in a fibre and isexpressed as a percentage of the totalweight.It is a measure ofthe am ount ofwaterheld under any particularset of circumstances.The moisture contentisalw ays Iowerthan the regain. Fibres can presentgreatvariations in the amountofm oisture they w illabsorb. W oolhas a regain of16% cotton of8.5%,acetateonly of6%.Fibres,which can absorb sufficientmoisture, are most suitable for processing into clothing because ' they will absorbperspiration from the body and willhold considerable amountsofm oisture w ithoutfeeling clam my. The abilityofa fibreto absorb moisture willalso affectthe processing and finishing offibres. Fibreswhich easil y absorb moisture,willtherefore Iet dyestuffs penetrate moreeasily during the dyeing process. Synthetic fibres,which often absorb little moisture,are easily washed and dried by comparison wi th fibres,which absorb a lotofm oisture.On theotherhand, thisentailsthe phenom enonof electrostaticcharging. The strength ofafibre isaffected significantly by the w ateritabsorbs. Fibres,w hich easily absorbmoisture,willusuallybeIessstrongwhenwet(exceptforflaxancotton)andwillpresent increased elongation atbreak.One should also realize thatabsorption ofm oisture can also m ake the fibre sw ellto a considerable degree,w hich is im portantforfixating dyestuffs . NM URAL FIBER: tA.*.ew ' . &r..* .yY< jl* *P . . '. . .., ., .. j .,+, w k f 44:t*R. e.' . ' * a .w ... v . PX* *.> * e* . * t.lk; ..<.% .. A- * z . K.. ij .. .j . . 4k/. . wà!vv1 t. J &' / 4.* r* .. . . * .. (e .. . .1 .. w . ;. . n . .7qj . .. W * G FI*ER o 4) ,.t... >.: .L' . y: . tjroo w..p) -'. .k. .:.. ...... ;.m . . > - y : . .. : ..j pk... . t .., fk ,# ..#. '. p'z . eJ . '/ej. 'f '?:' < I r t4w, )m /f . x. s.u .. ,4 ! (e - #Ikw@- ) L ï . : sj 1: . gy , . ' . e . -. #% k. ,4# . . a, ,. . . > uNw .. . pusvj 11 Elassification ofTextile Fibres: Textile Fibres Man-madeFibres NaturalFibres Animalfibre Vegetablefibre (Protein) (cellulose) M ineral Syntheticfibre Regenerated Other fibre (SYntheti cpol ymer) fibre (carb on,gl a ss,metal , cerami c,etc.) (Asbestos) tnaturalpol ymer) Silk W ool Hair (sheep) (alpaca,camel ,cow,goat, horse,rabbitetc.) Alginate Rubber Regen Regen Cellulose (elastodi erated er3ted ester ene) protein cellulo (azlon) -se (ra on) Animal(casein) Vegetable 1 1 Acetate Triacetate Seedfibre Bastfibre Leaffibre (cotton#coir) t fl ax-hemepjute,rami e, (auaectac,.s isal tc.) ) i i i i Pol ymethyl Polyolefin Pol yvinyl -eneur ea derivatives Viscose Cupro Modal Lyocell t t t Pol yure Polyamide Pol yimide Arami d -thane ornylon t Polyester Synthetic polyisoprene N Non-segm ented Polyethylene Pol ypropylene i ) Acrylic M odacrylic pplyurethane Chlorofibre segmented polyurethane (elastane,spandex,Lycra) ) ) ) Flourofibre Trivinyl Polystyrene j C i l 12 Fibre Identification: escience. Atonetime, The identificationoftextilefibresisavew importantpartofthestudyoftextil simpIefibreidentificationwasa relati vel y easytask;mostconsumerscouldtellbyappearanceandhand whetherafabricwascotton,wool,silk,orIinen.Oncethefirstmanmadefibreswere introduced,the processbecame abitmore difficult.Consumersusuallycould identifythe fibrecompositionoffabrics madeof100 percentrayonoracetate,butblendsofsomefibreswere difficult to identify.As more fibres w ere introduced, the task becam e progressively m ore difficult.Today,sophisticated techniquesare usually required foraccurate fibre identification. The purpose ofthe Textile Fibre ProductsIdentification Actwasto provide inform ation on fibre contentoftextilesatthe pointofsale.Consumerswere atonce relieved ofthe responsibilityto identify fibre content of items they purchased; howeverzprofessionals working with textile productsstillm ust be able to identify fibres accurately.Such individuals include retailerswho suspectsome textile productsthey boughtforresale have been Iabeled inaccurately;customs osicialswho m ustidentify imported fibres;dry cleanersw ho m ustclean an item from which aII the labels have been rem oved; extension hom e econom ists w ho are asked to help solve a consum er's problem w ith a textile product; and forensic scientists w ho m ust use a textile sam pleto help solvea crim e. Formostindividuals,the only information needed isa qualitative analysisoffibre content:what fibre orfibresare presentin this product? Forothers,a quantitative analysis ofthe product is also im portant: in w hat percentages are the fibres present? W ith the num bers of fibres availabletoday and the varietyofblendsbeing produced,neitheranalysisiseasy. M ethods for qualitative identification of fibres include such procedures as burning tests, m icroscopy,densi ty determ ination,m oisture regain analysis,dye staining,chem icalsolubility, melting point determination,infrared spectroscopy,and chrom atography.Sim pli fied versions ofthe firstsix proceduresare relatively easy to pedorm in m ostIaboratories.They require the use of a drying oven, an analytical balance sensitive to 0.005 gram, a com pound light microscope capableof200 x magnification,laboratory glassware,and a suppl y ofchemicals. A. Burning Test: The burning testis a good prelim inary testforcategorizing fibres.Observation ofburning provides information on behaviorin a flame,sm oke generation,odorduring burning,and ash or residue.lt never should be used as the only method of identifying a fibre,but it provides valuable information that may be used with other evidence to m ake a positive identificationofan unknown fibre. Blendsoffibres are difficultto testusing this procedure.Tbe reaction ofthe predom inant fibre may m ask the presence ofa second fibre,which could have entirel y different burning characteristics. Finishes, especially flam eretardant finishes, can also give m isleading inform ation. Althoughthe testiseasyto perform,itdoesinvolve the use ofanopenflame,making it necessaryto observe certain safety precauti ons.Use a sm allflam e source in an area w here there is no dangerofigniting otherm aterials.A candle in a stable base ora smallalcohol lamp is preferable to a hand-held m atch.A nonflam mable pad should be used underthe burning m aterialto provide protection from molten drip and sm oldering ash.Do nottouch ash ortweezerswhile they are stillhot.
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