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TRAININGSTRETCH&BLOWMOULDING拉伸吹制1.THEORETICALPART原理部分TRAININGTableofcontents内容总揽Thermoplasticpolymers聚合体的热塑性GeneralcharacteristicsofPET一般特性SBMprocessexplanation拉伸吹制过程解释Heatingandconditioningprocess加热调整过程Stretch/blowingprocess拉伸吹制过程12345TRAININGCH2=CH2Ethylene乙烯基Polyethylene聚乙烯-CH2-CH2--CH2-CH2--CH2-CH2--CH2-CH2-例如:Polymers聚合体:definition定义Polymerchains聚合体链:ahighmolecularmasssubstancecharacterizedbytherepetitionofoneormoretypesofmonomericunits由一种或多种单体副本组合而成的高分子化合物Monomer单体:asimplecompoundwhosemoleculescanjointogethertoformpolymers分子组合在一起可形成聚合体的一种简单化合物()nMonomer单体Polymer聚合体Polymerization聚合n1001TRAININGPET(PolyEthyleneTerephthalate聚对苯二甲酸乙二醇酯),是由PurifiedTerephthalicAcid纯对苯二酸(PTA)和EthyleneGlycol乙烯乙二醇(EG)两种原料化合形成的聚脂,这两种石油加工物在反应器内形成聚脂1PET的原料和制造“POLYESTER”聚脂•POLY=MANY许多•ESTER=joiningofanACIDandaGLYCOL酸和乙二醇的连接物EGPTAEGPTAEGPTAEGPTAEGPTATRAININGPolymers聚合体:结构Thechainstructuredependingfromthemonomer链结构由单体的泛函性组成决定functionality(2or3)1Monomer单体直线状(PET,HDPE)树枝状(LDPE)网状(PU)F平均泛函性:F=2线性F2.8网状2F2.8树枝状TRAININGPolymers:thermoplastic&thermosetting(1)聚合体:热塑性和热硬化性(1)1直线状和树枝状连接聚合体链结构如何能影响材料性质?链间相互之间可以滑动热塑性加热变软,冷却变硬,在软化状态(温度高于Tg)通过吹制成型聚合体举例:PE,PP,PET,Nylon,PVC,PC…典型工艺:挤压,注塑,吹制...TRAINING网状连接聚合体链间相互之间不能滑动因为它们之间有非常坚固的化学连接聚合体举例:Epoxyresin环氧树脂,siliconresin硅有机树脂…典型工艺:铸造,注射,挤出,压缩(聚合作用在成型后发生…)热硬化性通过加热或其它处理(化学,光学…)不能通过加热软化,不可熔融和溶解Polymers:thermoplastic&thermosetting(2)聚合体:热塑性和热硬化性(2)1TRAININGPolymers:omopolymersandcopolymers(1)Omopolymer:polymerwherealltherepetitiveunitsareofthesamekindCopolymer:polymerwheretherepetitiveunitsareoftwodifferentkinds.Inmanycases,asmallquantity(24%)ofdifferentmoleculas(i.e.isophtalicacid)areaddedtoethyleneglycolandterephthalicacidinordertoimproveprocessabilityoftheresin.Monomer“A”Omopolimer“A”Copolimer“A+B”Monomer“B”2TRAININGMonomer“A”Monomer“B”AlternatedAblocchiRandomGraftTheorderanddistributionofthe‘B’monomersinthechainchangethematerialbehaviour.Polymers:omopolymersandcopolymers(2)2TRAININGPET:链长度(1)Thepolymermechanicalbehaviourdependsonthechainsaveragelenght.聚合体的机械特性由链平均长度决定链越长则链与链之间的可滑动量越小IV=IntrinsicViscosity固有粘度Quantityproportionaltochainslength.It’sthemeasureofthemobilityofthepolymerchains.链长度所占比例反映了聚合物的滑动性能短链IV低,链滑动性高,机械强度低长链IV高,链滑动性差,机械强度高2TRAININGPET:链长度(2)Fibergrade纤维等级Specifications:短链结构(平均长度100units)IntrinsicViscosity固有粘度=0,5–0,7dl/gacetaldeydecontent乙醛含量高(AA)Applications:filmsandfibers胶片和纤维PET可有两种状态存在:(fiber)纤维等级和瓶子等级挤压机Flakes切片切割机单体Reactor反应器冷却器Productionprocess:Fusestatepolycondensation2TRAININGPET:链长度(3)瓶子等级Specifications:长链结构(平均长度130units)IntrinsicViscosity固有粘度=0,74–0,86acetaldeydecontent乙醛和水含量低用途:瓶子Productionprocess生产工艺:polycondensation固态缩聚颗粒料N2N2orvacuumPET纤维等级1stCrystallization结晶150°C–200°C2nd结晶150°C–200°C固态缩聚220°C冷却N2orvacuumN2orvacuumAAandH2OAAandH2OAAandH2O2TRAININGPET瓶子等级瓶子等级PET是一种高IV,低AA的树脂2机械强度差气体渗透性高结晶率高熔点低低IV机械性能好气体阻隔性好结晶率低高IV熔点非常高有热降解的危险非常高IV加工性能0.74-0.84机械性能和气阻性能TRAININGPET:morphology结构形态(1)PET的链之间怎么排列和组织?(颗粒)opaque白色不透明(瓶坯)熔融+冷却Transparent透明(瓶子)拉伸+吹制Transparent透明2TRAININGCrystallinestate结晶态Tm250°C310°CPET:结构形态(2)2gasgasgasgasAlignedchainsegments按链段排列:•Opaque不透明•机械性能和热阻性好•易脆裂•气阻性好•熔化过程没有软化阶段温度在Tm以下不能变形TRAININGPET:结构形态(3)Amorphousstate无定型态聚合体链没有特殊的排列:•Transparent透明的•Poorchemicalresistance低化学阻抗•Elastic有弹性•Highgaspermeability高气体渗透性•Softensbeforemelting熔融前有软化阶段gasgasTg70°C160°C250°C320°C温度在Tg之上可变形Tm2TRAINING定形态(straininducedcrystallization应变结晶)容器生产的理想需求•Transparent透明•highmechanicalproperty高机械特性•highbarrierproperty高气阻性无定形态PET少量结晶态被无定形态随机环绕如何适应这种结构形态?加热到高于Tg塑性变形定形态PET定形态和无定形态PET:结构形态(4)2Biaxialoriented双轴向的单轴向的TRAININGPET是一种吸湿的树脂,有从外界吸收水分的倾向。很多因素决定水分的吸收量,如:保存时间,温度,环境露点,树脂的结晶率。PET在无定形态要比结晶态吸水速度快。Theamountofwaterabsorbeddependsonvariousfactorsthatisstoragetime,temperature,environmentdewpoint,crystallization%oftheresin.PETintheamorphousstateabsorbsmoisturemorequicklythanincrystallinestate.PET:Environmentmoistureabsorption外界湿气的吸收2TRAININGPET:吸湿对拉伸吹制的影响Thewatermolecularstrappedbetweenthepolymer’smolecularchainsbehavesasalubricant.聚合体分子链之间的水分子表现为润滑作用。SoitbecomeseasiertostretchthematerialbutthisalsohasanegativeeffectonbottleshrinkagethroughtheNSRrise.所以它使拉伸变的容易，但同时因为自然拉伸率的上升对瓶子的收缩有负面影响315-20ppmofH201000-2000ppmofH20PET样品(无定形态)25Kgf1mm伸长10Kgf1mm伸长TRAINING3PET:张应力特性TensileStressBehaviour(1)IfanamorphousPETsampleissubjectedtoatensilestressimportantconsequencescanbeobtainedonitsmolecularstructure.Theybasicallydependsonthetemperatureatwhichstressesareappliedtothematerial.ElasticStrain弹性应变:Oriented被导向PlasticStrain塑性应变:Stretched拉伸TRAININGPET:张应力特性TensileStressBehaviour(2)3Howtheplasticsamplemodifiesduringtheelongationsteps塑料样本在延长过程中如何变形ELONGATION延长STRESS压力TRAININGSBM拉伸吹制管理工艺:基本原理拉伸是自我限制的为什么PET能被拉伸?延长NSR自然拉伸率STRESS压力STEEL钢CRACKING断裂PETFORHAVINGFURTHERDEFORMATIONISNECESSARYSTRESSINCREASING如果需要更大的变形需要增加压力3TRAININGSBM拉伸吹制管理工艺:基本原理哪种情况是最好的拉伸?延长NSR自然拉伸率STRESS压力UNSTABLE不稳定拉伸过度拉伸最适宜的拉伸3TRAININGSBM拉伸吹制管理工艺:基本原理Thestretchingcanbeadjustedbyworkingonthethermalprofile拉伸的调整可通过改变加热曲线来完成ELONGATION伸长STRESS压力1.拉伸度越高需要的温度越高2.厚度是由加热曲线控制的TT2T1e2e13.拉伸速度越快，需要的温度越高V3TRAININGSBM拉伸吹制管理工艺:拉伸率Thestretchingratiodependson