聚合物的基础培训（basic training for polymeric）.ppt

Lesson13Ambienttemp,uncertaintyissueIntroductionforFUTI,GTI,RTI,RTC,天马行空官方博客：,*Explanationofthermalindices:Inorderofhoweasyitistoapplythethermalindicesare:Functional-useThermalIndex(FUTI):Genericthermalindex(GTI):Relativethermalindex(RTI):RelativeThermalCapability(RTC):,天马行空官方博客：,*Functionaluse:Thesetemperaturelimitstakeintoconsiderationtheuseoftheappliance,meaninghowlongtimeitislikelythattheapplianceisrunatthismaximumtemperature.Ifthistimeisshortertheallowedtemperatureishigher.Theassumptionmadebythestandardswritersisthatamaterialthatcanhaveanormallifetimeat50Ccanbeallowedtoberunatahighertemperature(say80C)ifitonlyrunningshortperiodsoftimeduringitslifetime.Sincecommonlyusedmaterialsallwillbeabletoruncontinuouslyat50Cormoreitisnotnecessarytodoinvestigationsintothematerialproperties.,Howtounderstand50Cormoreandmaterialproperties?Whatkindofmaterialpropertiesyounotnecessarytodotheinvestigation?.FUTI:(短期).从50度开始。.根据材料的使用条件(外壳或支持带电部件，长期工作，间隙工作)确定最大极限温度。.它与所用的材料没有关系(与产品使用条件有关系)。.材料厚度没有关系。.如果测出的温升超过FUTI，可以用GTI，RTI，RTC再来评估，不轻易判不合格。.间隙工作允许温度比长期工作外壳来的高，例:间隙工作外壳最大温度为80度，而长期产品的外壳温度是50度。,*Genericthermalindex:ThesetemperaturelimitsarebasedonthechemicalpropertiesofthematerialandisthesameapproachtakenbytheIECstandardsfortemperaturelimits.Experienceshowthatusingtheselimitsmaterialswillretainenoughoftheirpropertiesduringthenormallifetimeoftheappliance.Somematerialshavehigherlimitsthangivenusingthefunctionalusetemperaturesthismeansthatadvantagecanbetakenofthattheirpropertiesarebetterthanmaybeassumedforunknownmaterials.GTI:(短期).根据材料组成成份(ABS,PC，PBT，PP，尼龙，胶木)来决定的。如ABS为60度，PP为65度，胶木为150度，PC为80度。.根据该材料在绝缘系统中和电气设备中的使用性能特点来决定。.与材料厚度没有关系。如果温升超过，通过FUTI，RTI，RTC再作评估，不轻易判不合格。,*Relativethermalindex(RTI):-BaseduponhistoricalrecordTheRTIistestedbymeasuringthepropertyofinterestonthematerialasnewandthendoanacceleratedagingatelevatedtemperatures.Aftertheagingthematerialshallretain50%oftheoriginalproperty.Thisrequiresnoknowledgeoftheappliancecategory.ULnormallylisttheRTIforelectricalpropertiesandmechanicalproperties(withorwithoutimpact).AtthetemperatureoftheRTIitisexpectedthatthematerialwilllosesomeofitspropertiesduringthelifetimeofthematerialbutwillretainenoughofthepropertytobesuitablefortheapplication.Thereasonstheindicesaregivenfordifferentpropertiesarethatallpropertiesarenotlostatthesamerateandtemperature(e.g.somematerialsloosetheimpactstrengthfasterthattheotherproperties).Temperatureratingforelectricalproperties,mechanicalpropertiesorspecifiedpropertyLifetime:20years;Thepropertiesretain50%.,.RTI:.与长期特性有关。.RTI与相关特性如厚度，颜色等有关。.一个厚度或一个颜色相对应于一个RTI指数。.温度超过RTI，用FUTI或RTC用来评估，不轻易判不合格。.长期评估材料特性，一般为20年。.保证相对应特性的50(整个产品寿命周期内)。,*RelativeThermalCapability:Thiscouldbetestedbymeasuringthepropertyofinterestaftertheagingonasamplerepresentingtheactualapplianceandintheactualthickness.AsamplemaycomplyifitdidnotloosethepropertytoofastORofithadasurplusofthispropertytostartwith.Thetestvalue(dielectricstrength,impactenergyorother)wouldbereducedcorrespondingto50%.Longtimedegradationofaspecificproperty,RTC:(长期特性).在最大操作温度情况下，该材料在产品使用寿命内整个过程中，保证材料的关键特性(RTC主要是针对成品)。.RTC表明一种能力：就是说，当温度超过RTI时，还能保证特定的机械和电的性能，包括短期和长期的特性，不影响它的功能。.RTI与材料特性厚度是一一对应的。例如：不同的厚度对应不同的RTI，如果考虑该材料某关键特性和规定最小厚度，也就是说在最小厚度情况下，保证某关键特性的RTI就可以认为RTC。.因为通常材料做成成品，某些机械特性(如冲击)设计上是有余量，牺牲一些冲击特性，可提高使用温度，所以RTC温度可能会超过RTI温度。.不能随意评估而且这个产品评估结果不能照搬到别的产品上。评估时注意RTC是属于长期特性，短期特性也要满足要求。,E.g:,E.g:,4.Firetest:Partsofnon-metallicmaterialshallberesistanttoignitionandspreadoffireaccordingtothetestabove.Wedothefiretesttocheckthematerialpropertytoretardtheflame.Whatispolymericmaterial?Acompoundformedbychemicalreactionthatresultinlargemoleculeswhosemolecularweightisamultipleofthatoftheoriginalsubstance(monomer).Includesthethermoplastic,thermoset,elastomericmaterials.Thermoplastic热塑料easilysoftenedandre-softenedbyheating加热后易于成型Thermosetting热固性(Shaftinmotor)Curesbychemicalreactionandcannotbere-softened固化成型时有化学反应发生，不能重新成型Elastomer弹性材料Stretch2timesatroomtemperatureandregainshape在室温时,能拉伸2倍多长,并能恢复成原形,Functionalparts功能部件1)Enclosures,Barriers外壳，挡板2)Supportofliveparts支持带电部件*3)Supportofconnections固定联接4)Insulation(supplementaryorreinforced)绝缘(附加绝缘或加强绝缘)NonFunctionalparts:Decorativepartsliketrims,knobs,otherpartsnotlikelyignited,Standardintroductionandflammabilityrateofthepolymeric:UL94:Standardforthetestsforflammabilityofplasticmaterialsforpartsindevicesandappliance,coversflammabilityofpolymericmaterialsusedforpartsindevicesandappliances.(5V;94V-0,94V-1,94V-2;HB;HBF,HF-1,HF-2.etc)V:vertical;H:horizontal.5V:500W(125mmflame)verticalburningtest.(IthinkitissameasIEC707)V-0,V-1,V-2:20mmverticalburningtest.(SameasIEC707)HB:Horizontalburningtest.(IEC707testmethodissame)HBF,HF-1,HF-2:Horizontalburningfoamedmaterialtest.(TestmethodissameasIEC707),UL746A:Polymericmaterials-shorttermpropertyevaluations.(keywords:shortterm,brandnewsample)UL746B:Polymericmaterials-longtermpropertyevaluations.(keywords:longterm,ageing,20yearsorsomething)UL746C:Polymericmaterials-Useinspecificapplicationsinendproducts.(keywords:specificapplication,endproducts)For“applicationandendproducts”,youmustconsiderboththeshorttermandthelongterm.,C)HWIandHAIareoftenusedinULstandard.(UL746AorC)HWIandHAIareforthespecimensampleandforenduseproducts.ULyellowcardofmaterialisusuallyforthespecimenmaterialnotfortheenduseproducts.HWItestmethodisforthedeterminationofresistancetoignitionofplasticmaterialsbyanelectricallyheatedwire.PLC:PerformanceLevelCategoryPLC=0isthebestandPLC=5istheworst.PLC=5meansthatwithin7s,itwillignitionthematerial.,HAI(High