包装材料专业英语[定稿]

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1、第5、6讲Unit3PackagingMaterialsandContainers(第三单元包装材料和容器)Lesson1PaperandPaperboard(第1课纸与纸板)(概述，典型造纸机，纸板的加工方向与横向，表面处理与涂覆，纸特性，纸/纸板等级，纸盒)1.Introduction(概述)Definitionofpaper:paperisdefinedasamattedorfeltedsheetusuallycomposedofplantfiber.Paperhasbeencommerciallymadefromsuchfibersourcesasrag

2、s(linen),bagasse(sugarcane),cotton,andstraw.Modempaperismadealmostexclusivelyfromcellulosefiberderivedfromwood.Althoughtheword"paper"isderivedfromtheEgyptianterm,"papyrus^wasnotatruepaperinthemodernsense・Inventionofpaper:theinventionofpaperbyblendingcellulosefibersdidn'toccuruntilthe

3、beginningofthesecondcenturyA.D.Ts'aiLun,amemberofthecourtofthelaterHanDynasty,isgenerallycreditedwithdevelopingthefirstrealpapermakingprocessin105A.D.The"Fourdriniermachine^wasthefirstonthemarketandproducedahomogenous(single-ply)sheetofboxboardinvariousthicknesses.Itwassoonjoinedbyth

4、e"Cylindermachine"whichformedamulti-layered(multi-ply)typeofpaperboard・ThesemachineswerefirstinstalledintheUnitedStatesaround1830.•Paperboard,boxboard,cardboard,andcartonboardarealltermsusedtodescribeheavierpaperstock.TheInternationalOrganizationforStandardization(ISO)statesthatmater

5、ialweighingmorethan250gramspersquaremetre(511bper1,000sq.ft.)shallbeknownaspaperboard.U.S.practicecallsmaterialthatismorethan0.3mm(0.012in.)thickpaperboard.2.RepresentativePapermakingMachines(典型造纸机)(l)FourdrinierMachinesFourdriniermachines(Figure3.1)pumpfurnishfromaheadboxdirectlyont

6、oamovingwirescreenthroughwhichthewateriscontinuouslydrained.Fourdriniermachinesmayhaveasecondheadbox(Figure3.2)situateddownstreamofthefirstheadboxtoaddfurtherquantitiesoffurnishontothepartiallydewateredinitiallay-down.WireFigure3.1Furnishpoursoutoftheheadboxofafourdriniermachineandon

7、toanendlesswireorscreenwhereexcesswatercanbedrained.ThefibersremaintrappedonthescreenFigure3.2Paperisdewateredatthewetendofafourdriniermachine(2)CylinderMachinesAcylindermachine(Figure3.3)rotatesascreendruminavatoffurnish(Thepaperissometimescalledvatpaper).Asthewaterpoursthroughthesc

8、reen,fiberac