液态硅胶性能(LSR)英文版

LiquidInjectionMolding:ProcessingguideforSILASTIC®LiquidSiliconeRubber(LSR)andSILASTIC®FluoroLiquidSiliconeRubber(F-LSR)SolutionsRubberFabricationWehelpyouinventthefuture.™DowCorningMoldingofSILASTIC®LSRandF-LSRBacktocontentpageInjectionmoldingofLiquidSiliconeRubber(LSR)isoftenthepreferredchoiceofproducersofrubberparts.ThatisbecauseLSRsofferbetterend-productperformance,andtheinjectionmoldingtechniqueoffershighlevelsofautomationandalmost24x7production.LSRsarealsoidealforrubberpartsingeneralapplicationsaswellasforspecificmarketdemandssuchasfoodcontact.Now,inadditiontothewiderangeofSilastic®LSRsfromDowCorning,manufacturerscantakeadvantageofanewliquidsiliconerubberproduct–onethatcanwithstandextremetemperaturesandhighlyaggressivesolventsandotherchemicals:Silastic®FluoroLiquidSiliconeRubber(orSilasticF-LSRforshort)isaLSRwiththeperformancecharacteristicsofFSR.Thismakesitidealfortheautomotiveandaerospaceindustriesandforotherextremeapplications.ThisbrochurediscussesthebasicsofinjectionmoldingusingSilasticLSRsandF-LSRsandwhatmanufacturersneedtoknowtofullyexploittheassociatedtimesavingsandproductivityimprovements.ForfurtherinformationonSilasticLSRsandF-LSRs,pleasecontacttheDowCorningTechnicalService&DevelopmentdepartmentviayournearestDowCorningsalesoffices.PrefaceDowCorningMoldingofSILASTIC®LSRandF-LSRPreface2SILASTIC®LSRandF-LSR4General4HandlingPrecautions4TechnologicaladvantagesofSILASTIC®LSRandF-LSR5Applications6InjectionmoldingofSILASTIC®LSRandF-LSR7Viscosity7Injection8HoldingPressure9MaterialCushion9PressureintheCavity9MaterialSupply10Mixing10Dosing10BackPressure10OvermoldingOpportunities10VulcanizationspeedsandCycleTimes11CuringBehaviorofSilasticLSR12Post-Curing13PrinciplesofmolddesignforSILASTIC®LSRShrinkage14PartingLine15Venting15InjectionPoint16DemoldingandEjectorSystems16MoldMaterials17CavitySurfaceFinish18TemperatureControl18SelectionofmachineClampingForce19InjectionUnit19MeterMixer19OtherinjectionmoldingtechnologiesTwoComponentInjectionMolding20InjectionMoldingofOneComponentSilasticHCRRapidCure22StartingtheproductionTemperaturePreset24InjectionStrokeandFlow24SwitchoverandHoldingPressure25CuringTime25Demolding25ProductionEndandClean-Up26TroubleshootingforinjectionmoldingofSILASTIC®LSR27TableofcontentsDowCorningMoldingofSILASTIC®LSRandF-LSRBacktocontentpageDescriptionSilasticLiquidSiliconeRubber(LSR)waspioneeredbyDowCorningandintroducedtotherubberfabricationmarketplaceinthelateseventies.Morerecently,DowCorninghasintroducedanewLSRthatisfluorinated:SilasticF-LSR.ThisnewrubberisatrueLSRbutwiththeperformancepropertiesofaFSR.Thismeansitcanwithstandtheextremetemperatureconditionsandaggressivesolventenvironmentsofmodernautomotiveandaerospaceengines.TodaytheprocessingandproductadvantagesofSilasticLSRsareexploitedinmanyexistingandnewapplications.Abroadproductlineisavailablebothforgeneralapplicationsandforspecificrequirements.Moreover,manynewapplicationsarerapidlyemergingtotakeadvantageofthenewSilasticF-LSRs.KeyElementsofSilasticLSRandF-LSRSilasticLSRsandF-LSRsareliquidswithviscositiesthatvaryfromeasilypourabletopaste.Thesetwo-componentmaterialsaremostlyusedina1to1ratioandconsistofpolysiloxanepolymersorcopolymers,whicharevulcanizedbypolyaddition.InadditionF-LSRsarefluorinated.TechnicalServiceTheDowCorningapplicationtechnologyandthecustomerservicecentersprovidethefulltechnicalandsalessupportneededtoruninjectionmoldingusingSilasticLSRandF-LSR.PackagingSilasticLSRandF-LSRaresuppliedaslotmatchedkitsin200-litredrumsor20-litrepails.Theexactpackagingweightvaries,dependingonthedensityoftheproduct.Fordetailedinformationpleaserefertotheindividualproductdatasheet.UsableLifeandStorageWhenstoredatorbelow32°Cintheoriginalunopenedcontainers,DowCorningguaranteestheusablelifeoftheseproductsuntilthedateindicatedonthepackagingandtheywillhaveausablelifeofatleast6monthswhenshipped.Thisdateisshownbytheletters:EXP.(meaningexpire)followedbyfourdigits,whichstandforthemonth(lastday)andyear.Example:EXP.03/09meansusebyMarch31,2009.AproductsafetydatasheetshouldbeobtainedfromyournearestDowCorningsalesofficepriortouse.Attention:Beforehandlingreadtheproductinformation,productsafetydatasheetandcontainerlabelsforsafeenduseandphysicaland/orhealthhazardinformation.SILASTIC®LSRandF-LSRGeneralHandlingPrecautionsDowCorningMoldingofSILASTIC®LSRandF-LSRBacktocontentpageEasierProcessing•nocuredecompositionproducts(unlikeperoxides)•longpotlifeatroomtemperatureyetveryfastvulcanizationabove150°C•SilasticLSRsareeasiertomixandtoprocessthanSilasticHCRRapidCure•F-LSRsareeasiertomixandtoprocessthanhighconsistencyFSRs•easytopigment,providingendproductflexibility•SilasticF-LSRscanbeovermoldedontoplasticsthathavealowermeltingtemperatureFasterCycleTimes•SilasticLSRsandF-LSRsarefullycompounded,readytoprocess•justtwocomponents,mixed1:1•automatedinjectionmoldingprocesssimilartothermoplasticinjectionmolding•easydemoldingwithgoodhottear•rapidcuringatelevatedtemperatures•flashlessmoldingwithtightpartsizetolerancecontrol•postcuringfrequentlynotneededBetterEnd-Products•goodd