包装盒专业英语

包装盒专业英语包装盒专业英语包装盒专业英语Lesson3PaperandPaperboard第3课纸与纸板22020/12/3包装盒专业英语包装盒专业英语包装盒专业英语Lesson1Lesson3

PaperandPaperboard

第3课纸与纸板2020/12/32Lesson3PaperandPaperboar

Introduction

Definitionofpaper:·Paperisdefinedasamattedorfeltedsheetusuallycomposedofplantfiber.Paperhasbeencommerciallymadefromsuchfibersourcesasrags(linen),bagasse(sugarcane),cotton,andstraw.Modernpaperismadealmostexclusivelyfromcellulosefiberderivedfromwood.·Althoughtheword“paper”isderivedfromtheEgyptianterm,“papyrus”wasnotatruepaperinthemodernsense.-Inventionofpaper·Theinventionofpaperbyblendingcellulosefibersdidn’toccuruntilthebeginningofthesecondcenturyA.D.2020/12/33IntroductionDefinitionofpa

Introduction

Ts’aiLun,amemberofthecourtofthelaterHanDynasty,isgenerallycreditedwithdevelopingthefirstrealpapermakingprocessin105A.D.·The“Fourdriniermachine”wasthefirstonthemarketandproducedahomogenous(single-ply)sheetofboxboardinvariousthicknesses.Itwassoonjoinedbythe“Cylindermachine”whichformedamulti-layered(multi-ply)typeofpaperboard.ThesemachineswerefirstinstalledintheUnitedStatesaround1830.2020/12/34IntroductionTs’aiLun,amem

Introduction

Paperandpaperboard·Paperboard,boxboard,cardboard,andcartonboardarealltermsusedtodescribeheavierpaperstock.·TheInternationalOrganizationforStandardization(ISO)statesthatmaterialweighingmorethan250gramspersquaremetre(511bper1,000sq.ft.)shallbeknownaspaperboard.U.S.practicecallsmaterialthatismorethan300(0.012in.)thickpaperboard.2020/12/35IntroductionPaperandpaperbRepresentativePapermakingMachines

FourdrinierMachinesFourdriniermachines(Figure3.1)pumpfurnishfromaheadboxdirectlyontoamovingwirescreenthroughwhichthewateriscontinuouslydrained.Fourdriniermachinesmayhaveasecondheadbox(Figure3.2)situateddownstreamofthefirstheadboxtoaddfurtherquantitiesoffurnishontothepartiallydewateredinitiallay-down.2020/12/36RepresentativePapermakingMaRepresentativePapermakingMachines

Figure3.1Furnishpoursoutoftheheadboxofafourdriniermachineandontoanendlesswireorscreenwhereexcesswatercanbedrained.Thefibersremaintrappedonthescreen2020/12/37RepresentativePapermakingMaRepresentativePapermakingMachines

Figure3.2Paperisdewateredatthewetendofafourdriniermachine

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CylinderMachinesAcylindermachine(Figure3.3)rotatesascreendruminavatoffurnish.(Thepaperissometimescalledvatpaper.)Asthewaterpoursthroughthescreen,fiberaccumulatesontheoutsideofthescreen.Thisthinlayerofmattedfiberistransferredontoamovingfeltbeltthatpassessequentiallyoverfurtherrotatingcylinders,eachofwhichdepositsanotherfiberlayer.2020/12/39RepresentativePapermakingMaRepresentativePapermakingMachines

Figure3.3Asinglecylinderstationonacylinder-typemachine

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Cylindermachinesdewaterfurnishatthecylinderandpasteathinlayeroffiberagainstthefelt.(Figure3.4.)Figure3.4Acylindermachinewithsixcylindersatwhichapaperlayercanbeformed

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Thefibersofsubsequentlayersdonotintermingle,andthereforethebondbetweenthelayersisweak.Thedryendissimilartothatofthefourdriniermachine.Cylindermachinesdonothavethefourdriniermachine'slimitationonthenumberofstations,andsix-orseven-stationmachinesarecommon.Higher-caliperboardsforfoldingandsetupcartonsareusuallycylinderboards.Generally,papersaremadeonfourdrinierortwin-wireformers,whereasheavierpaperboardproductsaremadeoncylinder-typemachines.Extremelyheavyboardsaremadebylaminatingseveralthinnersheets.Atypicalcylinderboardconstruction(Figure3.5):2020/12/312RepresentativePapermakingMaRepresentativePapermakingMachines

Figure3.5Cylinderboardsaremultiplyboards.Anadvantageisthatthepliescanallbedifferent

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Twin-WireMachinesVertiformersandtwin-wireformers(Figure3.6)injectthefurnishbetweentwomovingwirescreens.Theadvantageisthatdewateringtakesplaceonbothsidesofthepaperandisthereforefast.Thesemachinescanproducesingleandmulti-plysheetswithidenticalformationatbothfaces.MachineDirectionandCrossDirection

Depositingafiber-and-waterslurryontoamovingwirebelttendstoalignfibersinthedirectionoftravel,knownasthemachinedirection(MD).Thedirectionacrosstheapermakingmachineandacrossthefiberalignmentisthecrossdirection(CD)(Figure3.7).Becauseofthisfiberalignment,paperisananisotropicmaterial;measuredpropertiesdifferdependingonthedirectioninwhichthepropertyismeasured.2020/12/314RepresentativePapermakingMaRepresentativePapermakingMachines

Figure3.6Watercanbesimultaneouslyremovedfrombothsidesofthepaperonatwin-wirepaperformer

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Figure3.7Fibersinamanufacturedpapersheettendtoalignthemselvesinthemachinedirection

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Figure3.8showstherelationshipoftear,stiffness,andfoldendurancetomachinedirection.Paperspecificationsheetsnormallyshowphysicalvaluesmeasuredinbothdirections.Packagedesignersneedtobeawareofpaper'sdirectionality.Cylindermachinestendtoalignfibersmorethanfourdriniermachines.TensilestrengthratiosinMDandCDforatypicalfourdrinierboardareabout2:1,whereasforacylinderboardtheratiomightbe4:1orhigher,meaningthattheMDtensilestrengthisfourtimesgreaterthantheCDtensilestrength.Thegreaterthedegreeoffiberalignment,thegreaterthedifferenceinagivenpropertywhenmeasuredinMDandCD.Theratioofapropertyinthetwodirectionsisoftenusedasagaugeoffiberalignment.2020/12/317RepresentativePapermakingMaRepresentativePapermakingMachines

Figure3.8TherelationshipbetweenMDandtear,stiffness,andfoldenduranceproperties2020/12/318RepresentativePapermakingMaRepresentativePapermakingMachines

Cylindermachinestendtoalignfibersmorethanfourdriniermachines.TensilestrengthratiosinMDandCDforatypicalfourdrinierboardareabout2:1,whereasforacylinderboardtheratiomightbe4:1orhigher,meaningthattheMDtensilestrengthisfourtimesgreaterthantheCDtensilestrength.Thegreaterthedegreeoffiberalignment,thegreaterthedifferenceinagivenpropertywhenmeasuredinMDandCD.Theratioofapropertyinthetwodirectionsisoftenusedasagaugeoffiberalignment2020/12/319RepresentativePapermakingMaRepresentativePapermakingMachines

SurfaceorDry-End,TreatmentsandCoatingsAfterthepaperisformedanddried,itisusuallypassedbetweenmultiplesetsofheavyrolls(Figure3.9.).This"calendering"operationhasmanyvariations,buttheprimeobjectiveistoironandsmoothoutthesurfaceofthepaperstocktomakeitmoresuitableforprinting.Calenderingalsocompressesthepapersheet,givingadenserproductandaglossiersurface.Starchisatypicalsurfacesizingusedtofillsurfacevoidsandreduceliquidpenetrationrate.2020/12/320RepresentativePapermakingMaRepresentativePapermakingMachines

Figure3.9Calenderingconsistsofpassingtheformeddriedpaperbetweensetsofheavyrolls.Thepapersurfacemaybedampenedtohelpinsmoothingit

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Tomeetthehighestopacity,gloss,brightness,andprinting-detailrequirements,papersarecoatedwithpigmentssuchasclay,calciumcarbonate,andtitaniumdioxide.Coatedpapersareusuallycalled"clay-coated"regardlessoftheactualformulation.Coatedpapersarecalenderedtomaintainahigh-quality,smoothsurface.Inaddition,highlysizedandclay-coatedboardscanbedifficulttobondwithwater-basedadhesivebecauseofpoorliquidpenetrationandtheinabilityoftheadhesivetobondtotheunderlyingfibers.Wherenecessary,coatedboardsshouldhaveperforationsintheadhesive-bondareassothatadhesivecanpenetratetothebodyofthepaper.2020/12/322RepresentativePapermakingMaRepresentativePapermakingMachines

PaperCharacterizationCaliperandWeightIninch/poundunits:·Caliperisexpressedinthousandthsofaninchorin"points."Onethousandthofaninchis1point.(Forexample,a0.020-in.boardwouldbe20points.)·Containerboardforthecorrugatedboardindustryandmostpaperboardsarespecifiedbytheweightinpoundsper1,000sq.ft.,the"basisweight."·Finepaperscanbespecifiedbytheweightinpoundsperream.Areamis500sheets,buttheactualsheetsizecanvarydependingontheproduct.Inmostinstancesareamistakentobe3,000sq.ft..2020/12/323RepresentativePapermakingMaRepresentativePapermakingMachines

Inmetricunits:·Caliperisexpressedin"m".·Papermass/unitarearelationshipisreportedas"grammage",definedasbeingthemass(weight)ofpaperin1squaremetre(m2).Themetricconversionfactorsarelbs./l,000sq.ft.4.88=grams/m20.001inch25.4=(usuallyroundedto25)1mm=1,000BrightnessBrightnessisameasureofthetotalreflectanceofwhitelight.2020/12/324RepresentativePapermakingMaRepresentativePapermakingMachines

PaperandMoistureContentPaperishygroscopicandabsorbsandlosesmoistureaccordingtotheambientrelativehumidity(R.H.)andtemperature.Thephysicalpropertiesofpapervarydramaticallywithmoisturecontent,andinsomeapplicationsthemoisturecontentofthepaperduringprocessingmustbecontrolled.Becausephysicalcharacterizationvaluesdependonmoisturecontent,allpapertestingmustbedoneatapreciselycontrolledtemperatureandhumidity.Internationally,thestandardconditionsarespecifiedas23°Cand50%R.H.Paperishygroexpansive:whenitabsorbsmoisture,itexpands;whenitdriesout,itshrinks.Between0and90%R.H.,thedimensionscanchange0.8%intheMDand1.6%intheCD.2020/12/325RepresentativePapermakingMaRepresentativePapermakingMachines

Paper/foillaminatePaper/foillaminatePaper/foillaminate

at40%R.H.at20%R.H.at80%R.H.

Figure3.10Paper'shygroexpansivenaturecancauseunwantedcurlingwhenpaperisbondedtoanenvironmentallystablesurface

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Wheneverapapersheetislaminatedtoorcoatedwithamaterialthatisnotaffectedbymoisture(forexample,plasticfilm,aluminumfoil,orheavyprintorvarnish),thereisthepotentialforcurlingwhenthehumiditychanges.ViscoelasticityPaperismoreorlessviscoelastic,dependingontherateatwhichloadisapplied.Simplyput,thefasteraloadisapplied,thegreatertheapparentstrength.Overlongloadingperiods,paperfibersmoveanddistortor"creep."2020/12/327RepresentativePapermakingMaRepresentativePapermakingMachines

PaperTypes:NewsprintandRelatedGrades.BookPapers.

CommercialPapers.GreaseproofPapers.NaturalKraftPaper.BleachedKraftsandSulfites.

TissuePaper.

LabelPaper.

PouchPapers.

Containerboards(linerboardandmedium).

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PaperboardGrades:Chipboard,Cardboard,Newsboard.BendingChipboard.LinedChipboard.SingleWhite-Lined(SWL)Paperboard.Clay-CoatedNewsback(CCNB).DoubleWhite-Lined(DWL)Paperboard.SolidBleachedSulfate(SBS).FoodBoard.SolidUnbleachedSulfate(SUS).2020/12/329RepresentativePapermakingMaRepresentativePapermakingMachines

PaperboardCartonsPaperboardprovidesaversatileandeconomicalmaterialnotreadilymatchedbyotherpackagingmediums.Onesignificantadvantageisthelowtoolingcostcomparedwiththatformaterialssuchasplastics.Effectivepaperboardpackagedesignisbasedpartlyonknowledgeofpaperandproductpropertiesandpartlyoncraftsmanshipandart.Paperboardpackagingcanbeconsideredinanumberofcategories:FoldingCartons.Foldingcartonsarebyfarthelargestandmostimportantgroupinpaperboardpackaging.Foldingcartonsaremadeasflatblanksoraspregluedformsthatcanbeflattenedforshipping.Theycanbemadeeconomicallyonhigh-speedproductionmachinery.Themajorityoffoldingcartondesignscanbeclassifiedasfallingintoeitherthetube-style(Figure3.11)orthetray-styledesignfamilies(Figure3.12).2020/12/330RepresentativePapermakingMaRepresentativePapermakingMachines

Figure3.11Agable-topcartonblankandanerectedgable-topcarton2020/12/331RepresentativePapermakingMaRepresentativePapermakingMachines

Figure3.12Asix-corneredBrightwoodtray,flatandassembled

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Thegable-topcontainer(Figure3.11)isbasicallyatube-stylecartonthathasfoundmanyapplications,particularlyfordairyproductsandfruitjuices.Theheavilysizedandpolyethylene-coatedboardiserectedandheat-sealedatthepointoffill.CombiblocandTetraPakaresimilar-appea