Chapter8

GeneralFinishingLecturer:Prof.Dr.YankeluChapter8

GeneralFinishing8.1Introduction8.2MechanicalFinishing

8.2.1StenteringHotairstenter(hotairjigtenter)(pinclip)8.2.2CalenderingCalenderingisapurelymechanicalprocessalthoughchemicalsmaybeusedtoenhanceandmakedurabletheresultsobtainedbycalendering.Calendersconsistofaseriesoffromthreetoelevenheavyrollersturningagainsteachother.Alternaterollsaremadeofpolishedchilledsteel,brass,castiron,etc.andmaybesolidorwithahollowcoreandmaybecoveredwithcotton,pith,paper,linenorhusk.

8.2.2.1RollingcalenderorswissingOnasimplerollingcalenderthefabricpassesaroundthebottomrollandthrough

thenip,aroundthenextrollandsoontothelastnip.Thistreatmentservestogiveafinalsmoothnesstotheclothandmakeitlessporousandopen.8.2.2.2Chasing(疊層軋光)Onthechasingcalendertheclothpassesthroughthecalenderinthesamemannerasintherollingcalenderandisthenfedbackthroughtherollsasecondtimesothattwolayersoffabricpassthroughthenipsatthesametime.Thefinishobtainedonachasingcalenderissofterbutfullerandwithlessofasheenthanwitharollingcalender.8.2.2.3FrictionCalendering

Inthistypeofcalenderingafrictionduetoadifferenceinspeedoftheclothandtherollsisthemostimportantfactorinthefinishobtained.Inthefrictioncalendertheclothpassesthroughataslowerspeedthanthethirdrollwhichisapolishedchilledsteelroll.Theclothpassesthroughthecalenderatthespeedofthetwolowerrollsandthedrivenpolishedrollrevolvesontheclothatahigherspeedandpolishesit.Thisgivesahighlyglazedsurfaceandclosestheintersticesinthegoodstogiveasmoothfinish.Ifthethirdrollisrunhotahighglazeisobtained.Ifresinsareusedtheglazeproducedwillberelativelypermanent.8.2.2.4Shreinering（電光）Theshreinercalenderhasaseriesoffinestriationsorlinesengravedonit,generallyabout250totheinch.Theselinesareengravedatananglewiththeconstructionofthecloth.Theshreinercalendergivesaveryhighbutdeepseatedlustertothecloth.Theeffectemphasizedlusterasapposedtotheglazewhichisobtainedwithafrictioncalender.Ongoodswhichhavebeenshreinercalendereditispossibletoseetheembossedlinesinthefabricunderapickglass.8.2.2.5Embossing（軋紋）Theembossingcalenderissimilartoafrictioncalenderexceptthatthetoprollisengravedwithapatternandturnsatthesamespeedasthebottomrolls.Beforerunningcloththroughanembossingcalenderthesoftrolladjacenttotheengravedrollisdampeneduntilthepatternoftheengravedrollisimpressedintothesoftroll.Aftertheimpressiononthesoftrollissufficientlydeepthecalenderisrununtilthesoftrollisthoroughlydry.Clothisthenrunthroughthecalenderandtheengravedpatternisembossedontothecloth.8.2.3LaserFinishing

8.2.4AirorMechanicalVibrancy8.2.5Raising&Sanding8.3Chemicaltreatment8.3.1SofteningTreatmentSoftenersaremostcommonlyusedasanaideinproducingadesiredhandorfeeltoanenduseitem.Theymustbechosencarefully,however,becauseunintentionally,theymaycreateundesirablesideeffectssuchascolorbleed,printwicking,yellowing,chlorineretention,nitrousoxideorozonefadeingorcrocking.Theiruseimprovesend-useperformancecharacteristicsandextendsthelifeofthetextilesotreated.BasicchemicalcompositionThebeginningoftextilesoftening,emulsionofmineraloiland/orsaponifiablefatsortri-glycerideswereused.Themostsimplemethodofclassificationofsofteningagentsisbylistingthemaccordingtotheelectricalorionicchargetheyforminsolution.A:Anionicstructures

Anionicsoftenersaretheoldestofallmaterialsusedtomodifythestiffnessorharshnessoftextiles.Theywerefirstbasedonnaturaloils,fats,andwaxes,butnowincludemanyproductsderivedfromsynthesizedfattymaterialssuchassulfate,sulfonate,sulfatedfattyester,etc.Finishingagentsmadefromanionicmaterialsprovideasoftpliablehandbutarenotdurable.Beingwatersoluble,theyareeasilyremoved.B:NonionicStructuresNonionicsoftenershavetheadvantageoveranionicandcationicsoftenersinthattheyarecompatioblewitheitheroftheothertwoclassesofsofteneraswellasothertextilefinishingagents.Nonionicsaresabletohartwater,salt,andalkalineearthmetals.Thenonionicsoftenersaremoredurablethananionics,butstillnotasdurableascationics.C:CationicStructuresNaturallyoccurringfiberssuchascottonorwoolpossesanioniccharacteristicsandarethereforecapabletoattractingcationicallychargedparticles.Thisattractioniscalled“substantivity”andprovidesthemechanismforunilizingcationicsoftenersintextileprocessing.Cationicsoftenersaresensitivetoanioniccompoundsandcanformstickyprecipitateswhenexposedtothem.Manycationicsoftenersaffect“white”andyellowthem.Theycanalsoaffectthelightfastnessofcertaindyes.Mostcationicsoftenersexhibitacertaindegreeofwaterrepellencyandofantistaticprotection.D:AmphotericsThisclassofsoftenercarriersbotha“negative”anda“positive”charge.Inacidicsolution,thesesoftenersbehaveasiftheywerecationicbecauseofthereactionofthedonorprotonwiththeunsharedelectronpair.Inalkalinemediums,anaminecarboxylatesaltisformed.Amphotericssoftenershavenevergainedmuchacceptanceasaclassandarerarelysoldasapureformbutinblendswithothermaterials.E:PermanentSoftenersTheyshouldbeabletobechemicallybounddirectlytothecellulose/syntheticblendwhichwillinsurepermanence.(seealsop.293)F:SiliconeSoftenerTypesTheyareusedtoproduceanenduseperformanceandqualitythatcannotbeobtainedwithcon