高分子材料與應用(英文版)-Chapter-7-Coatings-and-Adhesives課件

高分子材料與應用（英文版）Chapter7CoatingsandAdhesives高分子材料與應用（英文版）Chapter7Coatin1IntroductionWhatarecoatings?Anysubstancesusedtocoverasurfaceandformedanlayeronto.Morespecifically,coatingsmeanspolymerbasedmaterialsusedtocoverasurface.Fourbasicingredients:

film-formingvehicles,pigments,solvents,andadditives.IntroductionWhatarecoatings?2IntroductionWhyCoatings?

Fordecoration:

Color,Gloss,etc.

Forsomefunctions:

erosionresistance,abrasionresistance,slipcontrol,fungalresistance,etc.ApplicationfieldArchitectureandfurniture(paint,漆);

Originalequipmentsmanufacture(OEM,usedinfactory);

SpecialCoatings(usedoutoffactory,forship,equipmentrepair,roadsignsetc.)IntroductionWhyCoatings?3IntroductionClassification

Basedonresintype:

alkyd,polyurethane,polyester,epoxy,…..Basedonenvironmentimpact:

Traditionalsolventcoatings:VOC→pollution

Environment-friendly:Waterborne,HighSolid,Powder,UV-curing…Basedonfinish(漆；末道漆)system:One-coat,Multicoatprimers,Intermediatecoats,andTopcoatsIntroductionClassification4Introduction

CoatingFormingProcess

1.Surfacecleaningandpretreatment2.Coatingsareapplied

dipping,spraying,electroplating…3.Theyformfilmsandcure

solventevaporation,bakingorairdrying,free-radicalpolymerizationIntroductionCoatin52.CoatingResins

AlkydsSynthesis:

fattyAcid+Polyacid+PolyolAdvantages:

lowcost;interiorexposuresgenerallygood.Disadvantages:

exteriordurabilityonlyfairApplication

finishingmetalandwoodproducts.PolyesterSynthesis:

Polyacid+Polyol+(Styrene)Advantages:

goodinterior&exteriordurabilityDisadvantages:

costishigherApplication:

furniture,appliances,automobiles,magnetwire2components:glass-reinforcedplasticbathtubs,lavatories,boats,cars2.CoatingResinsAlkydsPo6CoatingResinsEpoxiesmedium-tohigh-priced,goodadhesion(primersforautomotive),heatresistance(electricalinsulation),excellenterosionandchemicalresistance.poorultraviolet-lightresistance:usedoutdoors,tendtochalkanddiscolor.Acrylicsoutstandingweatherresistance(architecturalcoatings);lacquersandenamels(thetopcoatsfortheautomotive);excellentexteriordurabilityCoatingResinsEpoxies7CoatingResinsPolyurethanesprice>alkydsbut<epoxies.availableasoil-modified,moisturecuring,blocked,two-component,andlacquers.

abrasion-resistant,flexible,resilient,tough,chemical-resistant,andweather-resistant.

veryimportantfinishesinthetransportationindustry,includesaircraft,automobiles,railroads,trucks,andships;militarylandvehicles,ships,andaircraft(chemical&radiologicalresistance)CoatingResinsPolyurethanes8CoatingResinsChlorinatedrubber

usedasswimmingpoolpaintsandtrafficpaints.Fluorocarbonsnonstickproperties(forcookware).Polyamidestough,wear-resistant,arelativelylowcoefficientoffriction(forofficefurniture)Polyolefinsmoistureproof(forchemical-processingandfood-handlingequipment)CoatingResinsChlorinatedrubb93.PigmentsDefinitioninsolubleparticlesdispersedintheliquidportionofthepaint.Functiongivedesiredcolorandgloss,plusprovide"hidingability"(proportionedtorefractiveIndex)andprotection.ClassificationOrganic,inorganic,metallic;White&Color.3.PigmentsDefinition10

PigmentsPigmentDispersionThreeStepsWetting;separatinglargemass;StabilizingthesmallparticlesStabilizingMechanismsForsolventcoating:Polymeradsorption(entropyexclusion):layer>4.5nmForwater-borncoating:needdispersants;ionicinteraction,hydrophobicandhydrophilicbalance.PigmentsPigmentDispersion11

PigmentsPigmentVolumeConcentration(PVC)CriticalPVC

WithPVC↑(upto>CPVC),thepolymerscannotfillthespacesbetweenpigmentparticles→Holesappears,strength↓,adhesion↓.FactorsthatcontrolCPVCparticlesize↓,CPVC↑;sizedistribution↑,CPVC↑PigmentsPigmentVolumeConcen124.AdditivesFunctionaffectvariousareassuchascolor,waterresistance,slipcontrol,foamcontrol,andgloss.Antioxidant

easilycleavage,formfreeradical;e.g.,Phenoliccompounds,naphthol,primaryandsecondaryamines4.AdditivesFunction13Additives

AssociativethickenersFunction:thickenwater-based(mainlylatex)paintsthroughtheirhydrophobicinteractionwithotherpaintcomponentsThreeproducts:hydrophobicallymodifiedethoxylatedurethanes,HEUR,associativeacrylicthickeners,associativecelluloseetherAdditivesAssociati14AdditivesThickeningMechanism聚氨酯類增稠劑的增稠機理之一在于其分子可以水合溶脹而使水相增稠，其二是具有表面活性劑分子的性質(zhì)，其分子是線性親水鏈兩端接有親油基的高分子化合物，即在結(jié)構(gòu)中具有親水和疏水基團。這樣，在它的水溶液濃度超過一定值時就形成膠束。膠束能夠與乳液的聚合物粒子、已吸附有分散劑的顏料顆粒相互締合形成空間網(wǎng)狀結(jié)構(gòu)，互相連結(jié)纏繞而使體系粘度增加。因而，聚氨酯類增稠劑也稱為締合型增稠劑。AdditivesThickeningMechanism聚15AdditivesOtheradditivesAcceleratorCuringagentsLightstabilizersDefoamerDispersingagent(dispersant)WettingagentsSurfactantAdditivesOtheradditives165.Film-formingProcessSolventEvaporationwithsolventvolatilization,viscosity↑,Pigmentmovement↓,sotoplayerwithoutpigments→glossycoatingvolatilizetoofast→toplayerformfilmfirst→coatinglayershrinkageLatexcombinationDifficultytoformglossysurfaceFilmformingTtoolow→molecularmovement↓,latexparticlescannotcombine.Tg↑,Minimumfilmformationtemperature↑.5.Film-formingProcessSolvent17CoatingFilmDefectsLeveling(流平)drivenforce:surfacetension(σ).peakarea:coatinglayer↑→solventvolatilization↓→σ>valleyarea→flowfrompeaktovalley.controlfactors:viscosity,layerthickness.Sagging(流掛)controlfactors:viscosity,layerthicknessSurfaceshrinkage(表面起皺)Surfacevolatilization(cure)>bulk→surfaceformfilmfirst→Surfaceshrinkage

Controlfactors:layerthickness,

volatilization(cure)speed.CoatingFilmDefectsLeveling(186.EnvironmentfriendlycoatingsUV-curablecoatingsLowVOC,minimumthicknesschange6.Environmentfriendlycoatin19BasiccomponentsofUVcurablecoatings

BasiccomponentsofUVcurable20UV-curableCoatingsAdvantagesLowVOC,lowenergycost,lowequipmentinvestment.DisadvantagesThicknesslimit:pigment;polymerizationshrinkagePhotoinitiatorleftover:poorexteriordurability.Applications

printingsinks;papercoatings;photo-resistsforprintedcircuitsandmicroeletronicsUV-curableCoatingsAdvantages21WaterbornecoatingsWater-reduciblecoatingsWater+Solventasfilm-formingvehiclesCanusehighMwResinLownonvolatileweightWater-solublecoatingsWaterassolventLowwaterresistantLatexcoatings(乳膠漆)LowVOC,HighMw.DifficultytoformhighglossycoatingAdditivecomplication:dispersants,thickeners,etc.Usedinarchitecture.WaterbornecoatingsWater-reduc22ElectrocoatingOrganiccoatingsaredepositedonproductsfromanelectrolyticbathResinsmustcontainingchargesAdvantagesanddisadvantagesUniformfilmthicknesses,lowVOC,lesslabor-intensive;highcapitalequipmentcosts,highermaterialcosts,andmorethoroughpretreatment.Application:BottomcoatingforCars;metalproducts.ElectrocoatingOrganiccoatings23PowderCoatingsResintypeThermoplastic&ThermosettingFilmformationonpreheatedproductsCoatingMethodsFluidized-bedpowdercoating.Electrostaticfluidized-bedpowdercoatingElectrostatic-spraypowdercoatingAdvantages&disadvantagesLowVOC;thicknessupto500μm;lowenergycost.ExplosionRisk;cannotbeusedinthermosensitiveproducts.PowderCoatingsResintype24SummaryTraditionalcoatingshavefourbasicingredients.Environment-friendlycoatingshavebrightfuture.Coatingindustriesarereallytechnology-intensive.SummaryTraditionalcoatingsha25ADHESIVESADHESIVES26粘接是用粘合劑將被粘物表面連接在一起的過程。2surfacescanonlybejoinedwiththeestablishmentofbondsbetweenthem.Theexactnatureofthebonddependsontheadhesiveandthesurfacetobebonded.Itisimportantwhenjoiningmaterialswithtrue

adhesivesthatthesurfacestobecompletely

clean.Evenathincoatingofgreaseorsimilarmaterial

mayreduceconsiderablytheeffectivesurface

tensionofthesurface,impairingthebond.INTRODUCTION粘接是用粘合劑將被粘物表面連接在一起的過程。2surfa27TYPESOFADHESIVECanbedividedinto3types:a)Naturaladhesives

-canbemadefromanimal,vegetableormineralsources

b)Syntheticresinbasedadhesives

i)Thermosettingadhesives

ii)Thermoplasticsyntheticadhesivesc)inorganicadhesivesTYPESOFADHESIVECanbedivide28COMPONENTSOFADHESIVE(1)粘合物質(zhì)(2)溶劑(3)增粘劑(4)消泡劑(5)增塑劑(6)填料(7)防腐劑(8)稀釋劑COMPONENTSOFADHESIVE(1)粘合物質(zhì)29NaturalAdhesivesANIMALGLUEShavebeenusedforcenturiesincarpentryandjoineryObtainedfromtheskin/bonesofcattleandsheepAnimalgluesusuallysoldinpowderandmeltedin

warmwatertogiveasolutionofsuitableviscosity.Coolingoftheliquidafterapplicationresultsinrapidgelling,producingsomestrengthanddryingfinallyproducesatoughandrigidproduct.Removalofthewaterfromglueduringcuringis

essential;thewoodassistinthisprocess,dueto

absorption.NaturalAdhesivesANIMALGLUES30

Gluedjointsinwoodshouldbeasstrongas

thewood.Dampconditionwillreducestrengthofglue.Animalglueisnotsuitableforexternaluse

unlessadequatelyprotectedfrommoisture.Thegluewillhardengraduallyinthepotbut

canbesoftenedbyreheatingwithwater.Ifafailureoccursinsuchitemsitiseasyto

carryoutrepairsbysofteningthegluewith

water.Gluedjointsinwoodshouldb31AnimalGluesAnimalGlues32CASEINGLUESItisderivedasaprecipitatefromskimmed

milkbytheactionofacids.Gluesareobtainedinpowderformthatalso

containalkalinesolvent,necessarytodissolve

theglueonadditionofwater.Mixingiscarriedoutincoldandsettingis

partlybyevaporationorabsorptionofwater

andpartlybyanaturalgelationprocess.ItsadhesiontoporousmaterialisgoodItsmoistureresistanceissuperiorthananimal

glueCASEINGLUES33CaseinGlue–ADryGlueDerivedFromMilkCaseinGlue–ADryGlueDeriv34VEGETABLEGLUEMadefromstarches(淀粉)ordextrin(糊精)lowcostlimitedstrengthandlimitedmoisture

resistanceGumArabicisawatersolublevegetable

adhesiveoftenusedonstampsandgummed

paperenvelopes.VEGETABLEGLUE35CellulosePowderATypeofVegetableAdhesiveCellulosePowderATypeofVeg36WheatPasteATypeofVegetableAdhesiveWheatPasteATypeofVegetabl37THERMOSETTINGADHESIVESUREAFORMALDEHYDEOneofthecommonestadhesivesinjoineryforgeneralpurposes,producingastrongrigidjointiftheglue-lineisthin.Itprovidesastrongadhesioninapermanentlydryenvironment,curesfast,andisrelativelycheap.THERMOSETTINGADHESIVESUREAFO38Tomaketheadhesive,formaldehydeandurea

inaqueoussolutionareallowedtoreacttogethertoacertainstageandthereactionisthenstoppedwhiletheresinisstillliquid.Theyarebestsuitedforjoiningporousmaterialsuchaswood.Itisusedforfabricationofflushcolours,laminatedtimberanddecorativelaminates.Ithasagoodwaterresistancebutifveryhot

waterorprolongedwettingitcouldbreaksthe

resindown.Tomaketheadhesive,formalde39MELAMINEFORMALDEHYDERESINADHESIVES

Suppliedinpowderform&mixedwithwater

togiveacolourlessresin.Setonheatingto100°CGivegoodweatherresistance&expensive

thanureaformaldehydeadhesiveMELAMINEFORMALDEHYDERESIN40PHENOLFORMALDEHYDEavailableasliquidsthatpolymeriseonheating

totemperatureover100°C.UsedforassemblyofplywoodsheetsTheresinisapplied,thesheetsformedandthe

laminatesisthensubjectedtoahotpressthat

causeshardeninginaperiodofabout5min.Cold-curingphenolicadhesivesarealso

available.CanbeappliedforPlywood,blockboards,

flushdoorsPHENOLFORMALDEHYDE41EPOXYRESINSItformagoodbondwithalmostanymaterial.Itiswidelyusedforstructuraljointsbetween

manytypesofmaterialincludingglass,metal,

thermosettingplasticsandconcrete.HaveexcellentmechanicalstrengthHaveexcellentcreepresistanceResistanttoweather,acids,alkalisandmost

hydrocarbon.EPOXYRESINS42EpoxyResinEpoxyResin43EpoxyResinEpoxyResin44AlkylCyanoacrylateAdhesivesHaveadvantageofpolymerisingveryrapidly

whenspreadinthinfilms.Thereactionbeingcatalysedbywaterintheverysmallquantitiesrequiredwhichispresent

onmostsurfaces.Expensivesousesareconfinedtobondingof

smallobjectshavingsurfacesthatclosely

conformtooneanother.TheyformthebasisofSuperglues.Mustbehandledwithcaretoavoidbondingof

skintissues.AlkylCyanoacrylateAdhesives45THERMOPLASTICADHESIVES

Settingactionofthesemayduetocooling,

solventevaporationoremulsioncoalescence.Thisadhesiveismoreflexiblebutweakerand

morepronetocreepthanthermosetting

adhesives.So,theyarenormallynotusedforstructural

purposes.THERMOPLASTICADHESIVESSettin46POLYVINYLACETATEMostimportantthermoplasticadhesivein

building.Chiefapplicationbeingasawoodadhesivefor

internaluseandasabondingagentforconcrete.MostcommonlyusedinemulsionformThispolymerisobtainedfromacetylene&aceticacid.Theadhesivesetswhenthesolidparticles,on

evaporationorabsorptionofthemoisture,

coheretoformatough,clearfilmwhichisno

longerwatersoluble.POLYVINYLACETATE47PolyvinylAcetateUsedForBookBindingPolyvinylAcetateUsedForBoo48BITUMINOUS(瀝青)ADHESIVES

FormgoodbondswithanumberofmaterialsMoistureresistantFlexibleNaturalorSyntheticrubber&solventsmaybe

includedtogivethedesiredcombinationof

elasticityandstrength.Canbeobtainedin3formthatis

a)WaterBasedEmulsion

b)SolventTypesc)Hot-AppliedVarietiesBITUMINOUS(瀝青)ADHESIVES49WaterBasedEmulsions

-Formaneffectivebondbetweenporous

materialsinsituationswherelongtermtensile

stressesarenotpresent.

-Alsousedforlayingwood-blockflooringand

PVCorthermoplastictilesHot-AppliedVarieties

-Usedforwood-blockflooringandin

built-upfeltroofing.

-Applicationtemperatureintheregionof

150°C–200°CWaterBasedEmulsions

-Form50SolventTypes

-UsedinlayinglinoleumandforPVCandthermoplastictilesthoughtestshouldbecarriedouttoensurethatstainingdoesn’toccur. -Bothsolventandemulsiontypesrelyonsomedegreeofabsorbencyinthesubstratetoallowabsorption/evaporationofthewaterorsolvent.SolventTypes

-Usedinlayin51RUBBERBASEDADHESIVESThemostimportantrubberbasedadhesivesintheconstructionindustryarecontactadhesivesTheadhesiveisappliedtobothsurfacesandaftersolventevaporation,thesurfacesarecarefullybroughttogether,givingimmediateauto-adhesion.Latexessuchasstyrenebutadienerubber(SBR)arewidelyusedforfloorcoverings.Latex-modifiedcementsareusedforbondingceramictilestoavarietyofbackgrounds,includingmetal.RUBBERBASEDADHESIVES52ThankYouThankYou53高分子材料與應用（英文版）Chapter7CoatingsandAdhesives高分子材料與應用（英文版）Chapter7Coatin54IntroductionWhatarecoatings?Anysubstancesusedtocoverasurfaceandformedanlayeronto.Morespecifically,coatingsmeanspolymerbasedmaterialsusedtocoverasurface.Fourbasicingredients:

film-formingvehicles,pigments,solvents,andadditives.IntroductionWhatarecoatings?55IntroductionWhyCoatings?

Fordecoration:

Color,Gloss,etc.

Forsomefunctions:

erosionresistance,abrasionresistance,slipcontrol,fungalresistance,etc.ApplicationfieldArchitectureandfurniture(paint,漆);

Originalequipmentsmanufacture(OEM,usedinfactory);

SpecialCoatings(usedoutoffactory,forship,equipmentrepair,roadsignsetc.)IntroductionWhyCoatings?56IntroductionClassification

Basedonresintype:

alkyd,polyurethane,polyester,epoxy,…..Basedonenvironmentimpact:

Traditionalsolventcoatings:VOC→pollution

Environment-friendly:Waterborne,HighSolid,Powder,UV-curing…Basedonfinish(漆；末道漆)system:One-coat,Multicoatprimers,Intermediatecoats,andTopcoatsIntroductionClassification57Introduction

CoatingFormingProcess

1.Surfacecleaningandpretreatment2.Coatingsareapplied

dipping,spraying,electroplating…3.Theyformfilmsandcure

solventevaporation,bakingorairdrying,free-radicalpolymerizationIntroductionCoatin582.CoatingResins

AlkydsSynthesis:

fattyAcid+Polyacid+PolyolAdvantages:

lowcost;interiorexposuresgenerallygood.Disadvantages:

exteriordurabilityonlyfairApplication

finishingmetalandwoodproducts.PolyesterSynthesis:

Polyacid+Polyol+(Styrene)Advantages:

goodinterior&exteriordurabilityDisadvantages:

costishigherApplication:

furniture,appliances,automobiles,magnetwire2components:glass-reinforcedplasticbathtubs,lavatories,boats,cars2.CoatingResinsAlkydsPo59CoatingResinsEpoxiesmedium-tohigh-priced,goodadhesion(primersforautomotive),heatresistance(electricalinsulation),excellenterosionandchemicalresistance.poorultraviolet-lightresistance:usedoutdoors,tendtochalkanddiscolor.Acrylicsoutstandingweatherresistance(architecturalcoatings);lacquersandenamels(thetopcoatsfortheautomotive);excellentexteriordurabilityCoatingResinsEpoxies60CoatingResinsPolyurethanesprice>alkydsbut<epoxies.availableasoil-modified,moisturecuring,blocked,two-component,andlacquers.

abrasion-resistant,flexible,resilient,tough,chemical-resistant,andweather-resistant.

veryimportantfinishesinthetransportationindustry,includesaircraft,automobiles,railroads,trucks,andships;militarylandvehicles,ships,andaircraft(chemical&radiologicalresistance)CoatingResinsPolyurethanes61CoatingResinsChlorinatedrubber

usedasswimmingpoolpaintsandtrafficpaints.Fluorocarbonsnonstickproperties(forcookware).Polyamidestough,wear-resistant,arelativelylowcoefficientoffriction(forofficefurniture)Polyolefinsmoistureproof(forchemical-processingandfood-handlingequipment)CoatingResinsChlorinatedrubb623.PigmentsDefinitioninsolubleparticlesdispersedintheliquidportionofthepaint.Functiongivedesiredcolorandgloss,plusprovide"hidingability"(proportionedtorefractiveIndex)andprotection.ClassificationOrganic,inorganic,metallic;White&Color.3.PigmentsDefinition63

PigmentsPigmentDispersionThreeStepsWetting;separatinglargemass;StabilizingthesmallparticlesStabilizingMechanismsForsolventcoating:Polymeradsorption(entropyexclusion):layer>4.5nmForwater-borncoating:needdispersants;ionicinteraction,hydrophobicandhydrophilicbalance.PigmentsPigmentDispersion64

PigmentsPigmentVolumeConcentration(PVC)CriticalPVC

WithPVC↑(upto>CPVC),thepolymerscannotfillthespacesbetweenpigmentparticles→Holesappears,strength↓,adhesion↓.FactorsthatcontrolCPVCparticlesize↓,CPVC↑;sizedistribution↑,CPVC↑PigmentsPigmentVolumeConcen654.AdditivesFunctionaffectvariousareassuchascolor,waterresistance,slipcontrol,foamcontrol,andgloss.Antioxidant

easilycleavage,formfreeradical;e.g.,Phenoliccompounds,naphthol,primaryandsecondaryamines4.AdditivesFunction66Additives

AssociativethickenersFunction:thickenwater-based(mainlylatex)paintsthroughtheirhydrophobicinteractionwithotherpaintcomponentsThreeproducts:hydrophobicallymodifiedethoxylatedurethanes,HEUR,associativeacrylicthickeners,associativecelluloseetherAdditivesAssociati67AdditivesThickeningMechanism聚氨酯類增稠劑的增稠機理之一在于其分子可以水合溶脹而使水相增稠，其二是具有表面活性劑分子的性質(zhì)，其分子是線性親水鏈兩端接有親油基的高分子化合物，即在結(jié)構(gòu)中具有親水和疏水基團。這樣，在它的水溶液濃度超過一定值時就形成膠束。膠束能夠與乳液的聚合物粒子、已吸附有分散劑的顏料顆粒相互締合形成空間網(wǎng)狀結(jié)構(gòu)，互相連結(jié)纏繞而使體系粘度增加。因而，聚氨酯類增稠劑也稱為締合型增稠劑。AdditivesThickeningMechanism聚68AdditivesOtheradditivesAcceleratorCuringagentsLightstabilizersDefoamerDispersingagent(dispersant)WettingagentsSurfactantAdditivesOtheradditives695.Film-formingProcessSolventEvaporationwithsolventvolatilization,viscosity↑,Pigmentmovement↓,sotoplayerwithoutpigments→glossycoatingvolatilizetoofast→toplayerformfilmfirst→coatinglayershrinkageLatexcombinationDifficultytoformglossysurfaceFilmformingTtoolow→molecularmovement↓,latexparticlescannotcombine.Tg↑,Minimumfilmformationtemperature↑.5.Film-formingProcessSolvent70CoatingFilmDefectsLeveling(流平)drivenforce:surfacetension(σ).peakarea:coatinglayer↑→solventvolatilization↓→σ>valleyarea→flowfrompeaktovalley.controlfactors:viscosity,layerthickness.Sagging(流掛)controlfactors:viscosity,layerthicknessSurfaceshrinkage(表面起皺)Surfacevolatilization(cure)>bulk→surfaceformfilmfirst→Surfaceshrinkage

Controlfactors:layerthickness,

volatilization(cure)speed.CoatingFilmDefectsLeveling(716.EnvironmentfriendlycoatingsUV-curablecoatingsLowVOC,minimumthicknesschange6.Environmentfriendlycoatin72BasiccomponentsofUVcurablecoatings

BasiccomponentsofUVcurable73UV-curableCoatingsAdvantagesLowVOC,lowenergycost,lowequipmentinvestment.DisadvantagesThicknesslimit:pigment;polymerizationshrinkagePhotoinitiatorleftover:poorexteriordurability.Applications

printingsinks;papercoatings;photo-resistsforprintedcircuitsandmicroeletronicsUV-curableCoatingsAdvantages74WaterbornecoatingsWater-reduciblecoatingsWater+Solventasfilm-formingvehiclesCanusehighMwResinLownonvolatileweightWater-solublecoatingsWaterassolventLowwaterresistantLatexcoatings(乳膠漆)LowVOC,HighMw.DifficultytoformhighglossycoatingAdditivecomplication:dispersants,thickeners,etc.Usedinarchitecture.WaterbornecoatingsWater-reduc75ElectrocoatingOrganiccoatingsaredepositedonproductsfromanelectrolyticbathResinsmustcontainingchargesAdvantagesanddisadvantagesUniformfilmthicknesses,lowVOC,lesslabor-intensive;highcapitalequipmentcosts,highermaterialcosts,andmorethoroughpretreatment.Application:BottomcoatingforCars;metalproducts.ElectrocoatingOrganiccoatings76PowderCoatingsResintypeThermoplastic&ThermosettingFilmformationonpreheatedproductsCoatingMethodsFluidized-bedpowdercoating.Electrostaticfluidized-bedpowdercoatingElectrostatic-spraypowdercoatingAdvantages&disadvantagesLowVOC;thicknessupto500μm;lowenergycost.ExplosionRisk;cannotbeusedinthermosensitiveproducts.PowderCoatingsResintype77SummaryTraditionalcoatingshavefourbasicingredients.Environment-friendlycoatingshavebrightfuture.Coatingindustriesarereallytechnology-intensive.SummaryTraditionalcoatingsha78ADHESIVESADHESIVES79粘接是用粘合劑將被粘物表面連接在一起的過程。2surfacescanonlybejoinedwiththeestablishmentofbondsbetweenthem.Theexactnatureofthebonddependsontheadhesiveandthesurfacetobebonded.Itisimportantwhenjoiningmaterialswithtrue

adhesivesthatthesurfacestobecompletely

clean.Evenathincoatingofgreaseorsimilarmaterial

mayreduceconsiderablytheeffectivesurface

tensionofthesurface,impairingthebond.INTRODUCTION粘接是用粘合劑將被粘物表面連接在一起的過程。2surfa80TYPESOFADHESIVECanbedividedinto3types:a)Naturaladhesives

-canbemadefromanimal,vegetableormineralsources

b)Syntheticresinbasedadhesives

i)Thermosettingadhesives

ii)Thermoplasticsyntheticadhesivesc)inorganicadhesivesTYPESOFADHESIVECanbedivide81COMPONENTSOFADHESIVE(1)粘合物質(zhì)(2)溶劑(3)增粘劑(4)消泡劑(5)增塑劑(6)填料(7)防腐劑(8)稀釋劑COMPONENTSOFADHESIVE(1)粘合物質(zhì)82NaturalAdhesivesANIMALGLUEShavebeenusedforcenturiesincarpentryandjoineryObtainedfromtheskin/bonesofcattleandsheepAnimalgluesusuallysoldinpowderandmeltedin

warmwatertogiveasolutionofsuitableviscosity.Coolingoftheliquidafterapplicationresultsinrapidgelling,producingsomestrengthanddryingfinallyproducesatoughandrigidproduct.Removalofthewaterfromglueduringcuringis

essential;thewoodassistinthisprocess,dueto

absorption.NaturalAdhesivesANIMALGLUES83

Gluedjointsinwoodshouldbeasstrongas

thewood.Dampconditionwillreducestrengthofglue.Animalglueisnotsuitableforexternaluse

unlessadequatelyprotectedfrommoisture.Thegluewillhardengraduallyinthepotbut

canbesoftenedbyreheatingwithwater.Ifafailureoccursinsuchitemsitiseasyto

carryoutrepairsbysofteningthegluewith

water.Gluedjointsinwoodshouldb84AnimalGluesAnimalGlues85CASEINGLUESItisderivedasaprecipitatefromskimmed

milkbytheactionofacids.Gluesareobtainedinpowderformthatalso

containalkalinesolvent,necessarytodissolve

theglueonadditionofwater.Mixingiscarriedoutincoldandsettingis

partlybyevaporationorabsorptionofwater

andpartlybyanaturalgelationprocess.ItsadhesiontoporousmaterialisgoodItsmoistureresistanceissuperiorthananimal

glueCASEINGLUES86CaseinGlue–ADryGlueDerivedFromMilkCaseinGlue–ADryGlueDeriv87VEGETABLEGLUEMadefromstarches(淀粉)ordextrin(糊精)lowcostlimitedstrengthandlimitedmoisture

resistanceGumArabicisawatersolublevegetable

adhesiveoftenusedonstampsandgummed

paperenvelopes.VEGETABLEGLUE88CellulosePowderATypeofVegetableAdhesiveCellulosePowderATypeofVeg89WheatPasteATypeofVegetableAdhesiveWheatPasteATypeofVegetabl90THERMOSETTINGADHESIVESUREAFORMALDEHYDEOneofthecommonestadhesivesinjoineryforgeneralpurpos