Expancel Microspheres - Boud Minerals · microspheres will increase after expansion. The density of...
Transcript of Expancel Microspheres - Boud Minerals · microspheres will increase after expansion. The density of...
Expancel®Microspheresapplication guide -Paints and Coatings
Paints...............................................................12ThermalInsulationCoatings..................24ElasticWallandRoofCoatings.............28WaterbornePrintingInks........................36
Introduction to Expancel® Microspheres
Expancel®microspheresaresmallsphericalplasticparticles.Themicrospheresconsistofapolymershell
encapsulatingagas.Whenheated,theinternalpressurefromthegasincreasesandthethermoplasticshellsoftens,
resultinginadramaticincreaseofthevolumeofthemicrospheres.Thegasremainsinsidethesphere.
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ExpansionofExpancelmicrospheres.Thisresultsinadramaticdecreaseofthedensity.Typicalvaluesarefrom1000downto30kg/m3(8.35to0.25lbs/gal).
Thermomechanical propertiesExpancelisavailablewithexpansiontemperaturesintherangeof80-190
oC(175-375
oF).
Expancelcannormallybestoredforalongtimeatroomtemperaturewithoutnegativeeffectsontheproperties;veryhightemperaturesshouldbeavoided.
ElasticityExpancelmicrospheresregaintheiroriginalvolumewhenthepressureisreleased.Expancelcanwithstandseveralcyclesofloading/unloadingwithoutbreaking.
Thisisveryimportantwhenthemicrospheresareusedinshockabsorbentmaterialsbutalsowhenpumpingthemicrospheres;aloneorinvariousmixtures.
Properties ofExpancel® Microspheres
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ExpansioncurvesforsomeExpancelgrades.
Before0barg
During6barg
After0barg
IllustrationofwhathappenswhenExpancelDEisfirstputunderpressureandlaterreturnedtoambientpressure.
ExpansionTheexpansioncharacteristicsaremeasuredusingThermoMechanicalAnalysis(TMA).Thesampleisheatedataconstantrate(inouranalysis20
oC/min,36
oF/min)andthevolumeofthesample
ismeasured.Agraphrepresentingtheexpansioncharacteristicsofthesampleisrecorded(figure1).Fromthisgraph,thevaluesarecalculated.TypicalTMA-graphsofafewgradesareshowninfigure2.
ItisimportanttorememberthatifTmaxis140oC
(284oF)thisdoesnotnecessarilymeanthatthe
processtemperatureshouldbe140oC.
Theexpansionprocessisadelicatebalance.Therelationshipbetweenthesofteningofthe
shell,gastightnessoftheshellandpressureincreasefromthegasinsidethemicrosphereareimportant.Thebalanceisaffectedbyanumberoffactorssuchas:•Polymercompositionoftheshell•Typeofgasinsidethemicrospheres•Chemicalsincontactwiththeshell•Outerpressure•Freeexpansionorinamatrix•Typeofmatrix•Heatingrate
Thepolymercompositionoftheshellisimportantasitdeterminestheglasstransitiontemperatureandthegaspermeabilityoftheshell.Thegasinsidethemicrospheresdeterminesthepressureinsidetheshellatagiventemperature.
ContactwithchemicalscandecreasetheglasstransitiontemperaturesandtherebylowerT-startofthemicrospheres.Chemicalsmightalsoinfluencethebarrierpropertiesandincreasethegaspermeabilityleadingtothesmallerdensityreduction.
Insidethematrixthegaspermeabilitycanbeimprovedduetoitsbarrierproperties.IfthemicrospheresareunderpressurefromtheoutsidethedecreaseinpressurebetweentheinsideandtheoutsideoftheshellcanresultinahigherT-startandsmallerdensityreduction.
Across-linkingmatrix,egrubberorthermoset,canalsopreventsomeofthepossiblemaximumpressureexpansionofthespheres.
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ThegraphfromatypicalTMAanalysis.
TypicalgraphsofsomeExpancelgrades.
Thermal StabilityThethermalstabilityofdifferentgradesofpre-expandedmicrospheresshowsacleardifference.ThedifferentthermomechanicalbehaviourofvariousExpancelgradesmakesitpossibletochooseanoptimalgradeforeachprocessandapplication.
Rankingofthermalstability.
Particle SizeExpancelmicrospheresareavailableindifferentsizesbetween20and120micronsafterexpansion.
ThesizeofExpancelismeasuredbylaserdiffraction,LowAngleLaserLightScattering(LALLS).Themicrospheresinanygivensamplearenotallthesamesize.Thereisaparticlesizedistribution.
Allspheresinthissamplehaveapproximatelythesamerelationbetweendiameterandshellthickness.Thismeansthatthelargemicrospherehasgreatershellthickness-andhencealowergaspermeability-andthereforeitwillexpandslightlybetterthanasmallermicrosphereinthe
samesample.Thismeansthattheparticlesizedistributionthatisrathernarrowforunexpandedmicrosphereswillincreaseafterexpansion.
Thedensityofthemicrosphereshasaninfluenceontheparticlesize.Forinstance,size40microspheresatdensity30kg/m3(0.25lbs/gallon)hasaboutthesamesizeassize80microspheresatadensityof>100kg/m3(0.83lbs/gallon).
Chemical ResistanceExpancelcanbeusedincontactwithmanychemicals,includingsolvents,withoutdiscolorationornegativeeffectsonexpansionorotherproperties.
High PressureExpancelDUhasagoodresistancetohighpressure.TheabilityofExpancelDEtowithstandhighpressurevariesconsiderablywithdensityandparticlesize.Largermicrospheresandmicrosphereswithhigherdensityleadtobetterhighpressureresistance.
Closed CellsExpancelmicrospheresareclosedcells,whichisanimportantpropertyinmanyapplications.
Inawaterbornecoating,suchaspaint,thismeansthatthemicrosphereshavealowwaterabsorptionbutthecoatingwillhaveahighwaterpermeability.Thisiscausedbytheinterfacebetweenthemicrospheresandthesurroundingmatrix.
ExpancelGrade ParticleSize
820 Low 20 Low642 40551 80461 100920 120009 140 High930 High
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Inthisinterface,themoisturetransportisquickcomparedwiththemoisturetransportinthefilmitself.Thisallowsmoistureinthesubstratetoevaporate.
Gas TightnessThepolymershellofExpancelmicrosphereshasbeencarefullydesignedtohavelowgaspermeability.Thisisimportantinmanyapplicationssinceitkeepsthemicrospheresfromleakinggasintothematrix.
Gasleakageintothematrixcanproducepinholesinthematrixandanincreaseddensity.Thedegreeofgastightnessvarieswiththegrade.
Mechanical StrengthExpancelmicrospheresareabletowithstandmanycyclesofloading/unloadingwithoutbreaking.Howeverasthedensityofthemicrospheresdecreasesthisabilitywilldecreaseaswell.
Somechemicalsmayalsoaffecttheelasticityandmechanicalstrength.
Surface ModificationExpancelmicrospherescanbeusedtoachieveanicevelvet-likesurfacebyaddingasmallamounttoacoating.Thiscanbedoneonmetal,paper,fabrics,etc.
InsulationGas-filledclosedcellsarebeneficialinbothelectricalandthermalinsulationapplications.
Expancelmicrospheresareusedincablefillingcompounds.InPetrolatum,therelativepermittivitywasreducedfrom2.2to1.6byadding4%ofExpancelDE.
Thedensitywasreducedfrom900to450kg/m3(7.5to3.8lbs/gallon).
Thethermalconductivityofthermoplasticshasbeenreducedfrom0.2to0.06W/m*K(1.4to0.4Btu*ft/h*ft2*
oF).Thedensitywas
approximately300kg/m3(2.5lbs/gallon).
Thermalconductivitiesof0.07W/m*K(0.5Btu*ft/(h*ft2*
oF)arereportedon
1to1.5mm(0.4to0.6in)thickcoatings.
Internal PressureExpancelmicrospherescanbeaddedtoproduceaninternalpressureinthefinishedproduct.Thisisusedinmanyapplications,forexampleprintingblanketsandpipeinsulationforoffshoreapplications.
Expancelmicrospheresarealsousedtoimprovetheprocess.Theycan,forexample,bemixedwithafillerbeforeaddingabinder.Herethemicrospherescreateapressureinthemoldand,togetherwiththebinder,fillallthevoidsbetweenthefillerparticles.
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Anotherexampleisinjectionmoldingwherethepressureisusedtocounteracttheshrinkingthatoccurswhentheproductiscooled.
DispersabilityExpancelWUiseasytodisperseuniformlyinanaqueousdispersion,butcaremustbetakentochoosethecorrecttypeofdispersingequipment.Therearegradesthatareeasiertodisperseandthereareothersthataremoredifficult.
Thegradesthataremoredifficulttodispersemayrequirearotor/statormixerlikeaSilverstonmixer,whilethegradesthataremoreeasilydispersedmayonlyrequireasimplepropellerstirrerforproperdispersion.
ExpancelDUcanbeeasilydispersedusinggeneraldispersingequipment.
ExpancelWEisfairlyeasytodisperseinanaqueousdispersionusingproperequipment.
ExpancelDEisveryeasytodisperseusinggeneraldispersingequipment.Caremustbetakentoavoiddustingbecauseoftheextremelylowdensity.
Application TechniquesTherearemanydifferentprocessesinwhichExpancelmicrospherescanbeused:
Impregnation-acommontechniqueforprocessingnon-wovens
Lamination-Expancelinacorematerialwillcreatealightweightmaterialwithresilientproperties
Coating-Expancelinacoatinglayerwilladdthicknessandimprovesurfacecharacteristics
Spraying-Sprayingispossible
Molding-ExpancelDEcanbemixedwithmanythermosetmaterialstoformamouldedproductwithlowdensity
Mattingandanti-slip-Expancelcanbemixedinacoatingtomodifysurfacepropertieslikeglossandanti-slip
Injectionmolding-ExpancelDUorMBcanbeusedininjectionmolding
Extrusion-ExpancelDUorMBcanbeusedinextrusionofprofiles,cablesandhoses
ExpancelGrade ParticleSize
642WUDifficult 20 Difficult551WU 40461WU 80007WUFEasy 100054WUFEasy 120920WUFEasy 140 Easy
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DesignationEveryproducthasitsownuniquenamedependingonthecompositionoftheshell,theparticlesize,thedeliveryformand,ifthemicrospheresareexpanded,thedensityofthemicrospheres.
Thefirstthreetofourcharacters,thegrade,areacodeforthepolymertypeandtypeofhydrocarbon,egFG=foodgrade.
Thetwotofourlettersindicatethedeliveryform,egW=wet;D=dry;U=unexpanded;E=expanded;MB=masterbatch.
Thetwotothreedigitsaftertheletterindicatetheapproximateparticlesizeinmicronsafterexpansion.
Thefinald30indicatesthatthetruedensityofthedryproductis30kg/m3(0.25lbs/gallon).IftheproductisWE,thedensityvaluereferstothedensityasadryproduct.
Delivery FormsExpancelmicrospherescanbedeliveredinawidevarietyofdifferentforms.
Unexpandedproductsareusedwhentheprocessinggeneratesenoughheatforthespherestoexpandandthematrixallowsanexpansion.
Pre-expandedproductsareusedinprocesseswhereno,ornotsufficient,heatisgeneratedduringproductionorwhen,forexample,thematrixiscrosslinkingattemperatureslowerthantheexpansiontemperatureofthemicrospheres.
Wetmicrospheres(WU,WUF,WE)arechosenforprocessesthatcontainwaterwhilethedryversions(DU,MB,DE/DET)arechosenwhennowatercanbepresent.
Theunexpandedmicrospheresactasfoamingagentswhilethepre-expandedmicrospherescanbeseenaslightweightfillers.
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SolidContent DensityofExpancelVariety Description % kg/m3 lbs/gallon
WU Wet,unexpanded 60to80 1000to1300 8.3to10.8WUF Wet,unexpanded 60to80 1000to1300 8.3to10.8DU Dry,unexpanded >99 ~1000 ~8.3DUT Dry,treated,unexpanded >99 ~1000 ~8.3MB Dry,unexpandedmixedwithamatrix 62to65 1000 8.3WE Wet,expanded 15 ~30 0.25DE Dry,expanded >99 25to70 0.21to0.58DET Dry,treatedexpanded >99 25 0.21
DeliveryformsofExpancel
StorageExpancelmicrospheresareverystablewhenstoredinaplacewithnormaltemperatures.
ExpancelWU(F)mustbestoredinacool,well-ventilatedareainawaythatkeepsthemicrospheresfromdrying.
Ifmicrospheresbegintodrybecausethebaginthedrumisopenorpunctured,thedispersabilitywilldroprapidlycausingproblemssuchaswhitespotsorunevennessinthefinishedproduct.
Becauseofthis,itisveryimportanttocloseabagwhenitisopenedandonlysomeofthecontentused.
ExpancelDU(T)canbedamagedbyexcessiveheatduringstorage.Thisheatcancauseleakageoftheencapsulatedhydrocarbonresultinginpoorexpansion.
ExpancelMBmustbestoredinacool,well-ventilatedareaawayfromdirectsunlight.
ExpancelWEmustbestoredinacool,well-ventilatedareainawaythatkeepsthemicrospheresfromdrying.Poordispersabilitywillresultfromallowingdryingtotakeplace.
Separationcanalsotakeplaceasaresultofthelargedensitydifferencebetweenthemicrospheresandthesurroundingwater.Thisisbestpreventedbystoringthebagslyingdownflat.
ExpancelDE(T)mustbestoredinadry,cool,well-ventilatedareatocontrolairborneparticles.
Form pH Grade RecommendedUseUnexpandedWU(F) Acidic 820 DU(T),MB Acidic 642 Acidic 551 Acidic 461 Lowtemperatureapplications Acidic 051 Alkaline 920 Mediumorhightemperatureapplications Neutral 031 Neutral 007 VerygoodexpansioncapacityExpandedWE,DE(T) Acidic 461 Mediumsolventresistance Alkaline 920 Excellentsolventresistance
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Recommendations
Expancel® Microspheresrecommended grades
Polyester Putties461DET40d25920DET40d25461DE20d70(alternativegrade)
461DE20d60(alternativegrade)
Thermoset Materials461DET40d25920DET40d25(alternativegrade)
551DU40(alternativegrade)
Printing Inks Water007WUF40
Tech Textiles & Non-Woven551WU40007WUF40
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Paint461WE40d36461WE20d36(alternativegrade)
921WE40d24(alternativegrade)
461DE20d70(alternativegrade)
Cable Gel461DET40d25920DET40d25(alternativegrade)
Vinyl Foam909DU80051DU40(alternativegrade)
920DU40(alternativegrade)
Crack Filler461WE40d36
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Cultured Marble461DET40d25551DE40d42(alternativegrade)
Model Making Board461DET40d25551DE40d42(alternativegrade)
920DET40d25(alternativegrade)
Caulks and Sealants461DET40d25920DET40d25(alternativegrade)
UBC and Sealants909DU80930DU120
Thermoplastics930MB120951MB120930DU120(alternativegrade)
951DU120(alternativegrade)
Lightweight Foam551DU40551DE40d42930DU120(alternativegrade)
951DU120(alternativegrade)
Silicon Rubber053DU40909DU80920DET40d25(alternativegrade)
Shoe Soles093DU120930DU120951DU120950DU80(alternativegrade)
930MB120(alternativegrade)
Leather Finishing461WE20d36461WE40d36461DET40d25(alternativegrade)
Artificial Leather909DU80920DU40093DU120051DU40(alternativegrade)
Wall and Roof Coating461WE40d36461DET40d25(alternativegrade)
Modelling Clay461DET40d25461WE40d36(alternativegrade)
Thermal Insulation Coating461WE40d36921WE40d24(alternativegrade)
Concrete461WE40d36921WE40d24(alternativegrade)
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Expancel® Microspheresin Paint
Expancelgivesadvantagestopaint:n reduceddensityn betterapplicabilityn higherwater
vaporpermeabilityn lowerwaterabsorptionn betterfillingcapacityn lowermaterialcostn shorterdryingtimen improvedmattingeffect
n lowemissionofVOC
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Waterborne PaintsAsanadditivetowaterbornepaintsanExpancelWEgradeisrecommended.Theseareexpandedtoaverylowdensity,thetruedensitybeing36kg/m3(0.30lbs/gal).Theyareavailableinthreesizes,withameanparticlediameterofapproximately80,40and20µmrespectively.Thelowdensitymicrospheresaremoist,whichmakeshandlingeasier.921WE40d24isachlorine-freealternative.
Expancelgradesusedinthepaintindustry:
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Grade 461WE40d36 461WE20d36 921WE40d24ed
Particlesizeweightaverageµm 30-50 20-30 35-55
Truedensity(inair) 36+3 36+3 24+3 kg/m3(lbs/gal) (0.3+0.025) (0.3+0.025) (0.2+0.025)
Solidcontent% 15+2 15+2 15+1.5
Reduced WeightByusing0.5%Expancel,theweightofa12litre(3.17gal)paintpotwillbereducedfromabout18kg(39.7lbs)to14kg(30.9lbs).
Thedensityofthepaintdecreasesto1.20kg/cm3(10lbs/gal)and,thus,thevolumeperkgpaintincreasesby30%.
ApplicationThepaintcaneasilybeappliedbyrollerorbrushbecauseofthesphericalformoftheparticles.Sprayinginairlessspraygunsisalsopossible.AlightweightpaintcontainingExpancel,withequalviscosityasaconventionalpaint,doesnotsplashtothesameextentwhenusingaroller.Theexpandedmicrospheresarehighlyelasticandwithstandhardmechanicaltreatmentwithoutdamage.
Intexturedcoatings,Expancelmakesiteasiertogetthestructuralfillermoreevenlydistributed.
ThedryingtimeofapaintwithExpancelwillbeshorterduetoahighersolidcontentbyvolume.
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Water Vapor PermeabilityPaintswithExpancelWEaremorepermeablethancorrespondingstandardpaints.ExpancelWEcanbeusedasanadditivetoregulatethewatervaporpermeabilityinlightexteriorpaintfilmsandprimercoatings.
Water AbsorptionPaintswithExpancelWEaremorehydrophobicthancorrespondingstandardpaints.Oneofthereasonsforthedegradationanddestructionofapaintfilmisthewaterabsorption.TheadditionofExpancelWEwilldecreasethewaterabsorptioncausingadelayinthedestructionandreducetherateofdestructioninpaint.
Properties of Paints with Expancel®
Hiding Power - OpacityOneoftheobjectiveswhenmakingalightweightformulationwithExpancelistoreplacepartoftheheavyfillerswithExpancelmicrospheres.Itisthenimportanttoachieveaveryhighpackingdegreeinordertoimprovethehidingpower.Unfilledspacesbetweentheparticlesarenottoberecommendedinthiscaseasthemicrospheresthemselvescontributewithalotofunfilledspacesinthefilm.
Surface FinishExpancelmicrospherescanbeusedasamattingagentinpaintswithlowgloss.Themicrospheresprovideamattfinestructuredfinishtothesurface.
Filling CapacityApaintwithExpancelhasabetterfillingcapacity,whichmeansahighercapacitytocovercracksinthesubstrate.Thisisachievedbytheincreasedsolidcontentbyvolume.Anotheradvantageisshorterdryingtime.
ViscosityAsuitablelevelofviscosityofalightweightpaintwithExpancelcaneasilybeobtainedbyusingmoreorlessthickener.Adecreaseinviscositybyaddingwaterisnotrecommendedsincetheopacitywillbenegativelyaffected.
IfExpancelmicrospheresareaddedto
aconventionalformulation,ortoaformulationnotintendedtocontainanylightweightfiller,theviscositywillincreaseconsiderably.
Material CostExpancel
hasalowbinderdemandbecause
theoilabsorptiononavolumebasisisverylow.ThismakesitpossibletoincreasethePigmentVolumeConcentrationwithoutsacrificingquality.TherawmaterialcostsperlitrepaintwillbelowerwithExpancel
microspheres.
Astandardformulationofaninteriorflatwallpaintwillshowacostsavingof3-5%perlitrebyusingExpancel,whileanexteriorpaintwillshowacostsavingofapproximately7%.
Storage StabilityThestoragestabilityofthepaintwillnotbeaffectedwhenusingExpancel
microspheres
asalightweightfiller.ThereisnoriskofExpancel
microspheresflotatingataviscositysuitableforpainting.pHshouldbekeptbelow8.3inordertoavoiddiscolouration.
Health AspectsExpancel
microspheres
inlightweightpaintswill
notgivetheusersanyhealthorsafetyproblems.
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TwothingsareofutmostimportanceconcerningthepreparationofExpancel.TheadditionofExpancel
oughttotakeplacejustafterdispersing
theheavyfillersandtheperiphericalspeedshouldbehighenoughtodisperseExpancelWEmicrospherescompletely.
ThefollowingdispersionprogrammeissuitabletoobtaincompletelydispersedparticlesatthemanufacturingofalightweightpaintwithExpancelWE.
WaterDispersingagentsPreservativeDefoamerWettingagentPigmentOpacifyingextenderFillers
Themixtureisdispersedfor10minutesataperiphericalspeedofatleast10m/s(32.8ft/s).
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Expancel WE
ThickenerpH-bufferCoalescent
Dispersefor5minutesataperiphericalspeedofatleast10m/s(32.8ft/s).
Binder
Dispersefor5minutesatalowerperiphericalspeedeg5m/s(16.4ft/s).
DefoamerWater
Thecomponentsaremixedtogetherbymeansofahighspeeddissolver.Theingredientsareaddedintheordersuggested.Itisveryimportanttoachieveamixturewithnoagglomerates.
Preparation ofLightweight Paints with Expancel WE
Therefore,dispersionshouldtakeplaceinthreestepsduringpreparation:
1. fortenminutesafteradditionofthemineralfiller.
2. forfiveminutesafteradditionofthethickeners tothemixtures(ifcellulosethickenerin powderformisuseditmustbedissolved andthemixturethickenedbeforethedispersion ofExpancelWE).
3. forfiveminutesafteradditionofthebinder.
Theperiphericalspeedofthedissolvingdiscshouldbeatleast10m/s(32.8ft/s).Alowerspeedcanresultinincompletedispersionofthemicrospheres.Theair,whichisoftenwhippedintothepaintduringpreparation,isremovedbyaspecialdeaerationdiscinlaboratoryscale.
Ifnecessary,asmalleramountofasuitableanti-foamingagentcanbehelpful.Inthisphasethedissolvermayworkatalowspeedtogivetheairbubblesagoodchancetoescape.
PleasenotethatdispersionanddeaerationmightbemoreimportantforpaintswithExpancelWEthanforpaintswithoutmicrospheres.
Expancel461WE20d36isrecommendedduetoitsgooddispersability.
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Dispersability of Expancel DE
ThedryExpancelDEgradescanbesprayedwithwatertomakethehandlingeasier.TheDEgradesobtainaproperdispersionatloweragitationcomparedtotheWEgrades.
Thewettingprocedureisperformedrapidly.Themicrospherescanbewetteddirectlyinthebag.
TheviscositywasmeasuredwithaBrookfieldRVTViscosimeterspindle6.Therheologyoftheguidingformulationshowsapseudoplasticflow.
Theviscositywasdeterminedafterthreedaysofstorage.
Inordertokeeptheconsumptionofbinderonalowlevelinalightweightpaintitisofgreatimportancetocalculatetherightpackingdegreeoftheusedfillers.Insuchcases,partsoftheheavyfillerscaneasilybereplacedbymicrosphereswithoutadditionalbinder.
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Whenkeptinmetalcontainersitisnecessarytoaddanantirustagenttotheformulation,usuallysodiumnitriteandsodiumbenzoate.
Topreventthegrowthoffungiinplaceswithhighhumidityafungicidemaybeaddedtotheformulation.
Theguidingformulationsarebasedonlaboratorytestsonly.Aprospectiveusershoulddeterminethesuitabilityoftheformulationsbeforeadoptingthemonalargescale.
Comments to the Guiding Formulations
Formulation no 1Interiorflatpaintcontaining2%(0.3%dry)Expancel461WE40d36vscorrespondingstandardpaint.
Standard Modifiedwith2% Paint Expancel461WE40d36Water 400.0 409.0Sodiumtripolyphosphate,10% 6.0 6.0PigmentdisperserA,10% 6.0 6.0ProxelGXL 2.0 2.0TritonCF-10,10% 20.0 20.0Foamaster8034 2.0 2.0TyloseMHB30000YP 3.0 3.0TitaniumdioxideR-FD-1 120.0 120.0SocalP2 60.0 90.0MicrodolSuper 120.0 140.0OmyaBLP-2 118.0 50.0Expancel461WE40d36,15% -- 20.0Acrylicbinderemulsion,60% 100.0 100.0Texanol 10.0 10.0Foamaster0 2.0 2.0Water 16.5 11.5AMP95 2.5 1.0AcrysolTT-935,30% 12.0 8.5Total 1000.0 1000.0
Constants and properties
SpecificGravity g/cc(lbs/gal) 1.40(11.7) 1.22(10.2)SolidContent,weight % 49.8 47.8SolidContent,volume % 26.9 34.7ViscosityBrookfield#6,50rpm mPas 7900 5400PVC % 72.0 80.9HidingPower-Contrastratiogapclearance 180µm 98.8 97.5Filmthickness 75µmdry 97.8 97.5Brightness457mm 89.5 90.5Gloss60
o 2 2
pH 8.6 8.3Costsaving(approx) % -- 4.3
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Formulation no 2 - 3 - 4InteriorflatpaintcontainingExpancel461WE20d36vscorrespondingstandardpaint.
Standard Modifiedwith Paint Expancel461WE20d36 2% 3% 4%Water 245.0 255.0 255.0 275.0Sodiumtripolyphosphate,10% 6.0 6.0 6.0 6.0PigmentdisperserA,10% 6.0 6.0 6.0 6.0TritonCF-10,10% 10.0 10.0 10.0 10.0ProxelGXL 1.0 1.0 1.0 1.0Foamaster8034 2.0 2.0 2.0 2.0Tiona388 60.0 60.0 60.0 60.0SocalP2 100.0 130.0 145.0 160.0OmyaVioletD 170.0 140.0 140.0 140.0Calciumcarbonate5µm 160.0 105.0 75.0 50.0TalcumM15 50.0 50.0 50.0 50.0Expancel461WE20d36,15% -- 20.0 30.0 40.0CellosizeQP-30000H,3% 30.0 60.0 50.0 40.0CollacralPU85,30% 10.0 10.0 10.0 10.0RopaqueUltraE,37.5% 30.0 30.0 30.0 30.0Texanol 6.0 6.0 6.0 6.0Acronol290D,50% 100.0 100.0 100.0 100.0Foamaster0 2.0 2.0 2.0 2.0Water 12.0 7.0 22.0 12.0Total 1000.0 1000.0 1000.01000.0
Constants and properties
SpecificGravity g/cc(lbs/gal) 1.40(12.9)1.29(10.8)1.19(9.9) 1.12(9.3)SolidContent,weight % 61.2 56.1 55.3 54.7ViscosityBrookfield#6,50rpm mPas 6000 5700 54005300PVC % 81.0 86.0 88.0 89.0HidingPower(contrastratiogapclearance)180µm 99.4 99.0 99.0 98.6Spreadingrate(contrastratio98%) m2/l 10.3 9.5 9.6 9.8WetFilmthickness(contrastratio98%) µm 97.0 105.0 104.0 102.0Brightness457mm 86.2 86.8 86.8 86.9Gloss60
o 2 2 2 2
ScrubresistanceDIN53778 ca2000 ca2000 ca2000ca2000Costsaving(approx) % -- 4.6 5.1 5.7
Formulation no 5Exteriorhousepaintcontaining2%(0.3%dry)Expancel461WE20d36vscorrespondingstandardpaint.
Standard Modifiedwith2% Paint Expancel461WE20d36Water 186.2 166.5Natrosol250HR 3.8 3.5Oratan731,10% 20.0 20.0TritonCF-10,10% 20.0 20.0Sodiumtripolyphosphate10% 10.0 10.0Nopco8034 2.0 2.0Ethyleneglycol 10.0 10.0TitaniumdioxideRK-B2 200.0 200.0MicrotalcITExtra 70.0 100.0Syenex10NephelineSyenite 110.0 80.0Expancel461WE20d3615% -- 20.0Acrylicbinderemulsion,60% 330.0 330.0Propyleneglycol 10.0 10.0ProxelGXL 3.0 3.0Texanol 10.0 10.0NopcoNXZ 2.0 2.0Water 13.0 13.0Total 1000.0 1000.0
Constants and properties
SpecificGravity g/cc(lbs/gal) 1.39(11.6) 1.23(10.3)SolidContent,weight % 60.8 61.5SolidContent,volume % 41.0 49.0PVC % 39.0 56.0ViscosityBrookfield#6,50rpm mPas 4900 5000StorageStability 14daysat50
oC Pass Pass
HidingPower-Contrastratiogapclearance 180µm 98.7 98.3Filmthickness 75µmdry 98.2 97.7Brightness457mm 89.1 89.1Gloss60
o 5 2
pH 8.3 8.1Costsaving(approx) % -- 6.8
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Formulation no 6Texturecoatingcontaining3%(0.45%dry)Expancel461WE20d36vscorrespondingstandardpaint.
Standard Modifiedwith3% Paint Expancel461WE20d36Water 150.4 152.4ProxelGXL 2.0 2.0Potassiumtripolyphosphate10% 0.8 0.8Oratan731,25% 6.0 6.0FoamasterNXZ 0.8 0.8Titaniumdioxide 50.0 50.0Syenex20NephelineSyenite 100.0 70.0Calciumcarbonate,2µm 200.0 210.0CellosizeQP-15000H 6.0 6.0Acrylicbinderemulsion,60% 200.0 200.0Expancel461WE20d3615% -- 30.0BentoneEW,10% 4.0 2.0Texanol 10.0 10.0Ethyleneglycol 10.0 10.0StructurefillerQuartz-sand0.02-0.5mm 90.0 70.0StructurefillerQuartz-sand0.02-0.5mm 170.0 180.0Total 1000.0 1000.0
Constants and properties
SpecificGravity g/cc(lbs/gal) 1.70(14.2) 1.33(11.1)SolidContent,weight % 74.2 71.5SolidContent,volume % 54.0 60.0PVC % 70.0 79.0Costsaving(approx) % -- 7.8
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Expancel® Microspheresin Thermal Insulation Coatings
AddingExpanceltoaninsulationcoatingreducesconductivity,whichcanhelp
toreducepowerconsumption.
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ExpandedthermoplasticExpancelmicrosphereswithlowdensityareoftenusedasalightweightfiller.TherearealsoanumberofvaluablepropertiesthataretechnicallyimprovedwhenExpancelmicrospheresareincorporated.
Whenexpandedmicrospheresareaddedtoanacryliccoating,anessentialincreaseinthermalinsulationisachieved.Thisiscausedbygas-filledvoidsinthecoatingthatarecreatedbytheexpandedmicrospheres.
Thethermalinsulationcoatingisbasedonahighlyelasticaqueouspolymeremulsion.ThevolumeextentofexpandedExpancelmicrospherescouldbeadjusteddependingontherequiredinsulationcapacityofthecoating.
What Grade is Best?
Asthecoatingiscuredwithoutadditionalheat,wetpre-expandedExpancelmicrospheresarerecommendtobuildupafoamedstructureinthecoating;egExpancel461WE40d36orExpancel921WE40d24.Drypre-expandedgradesarealsoavailable.
Preparation
Thethermalinsulationcoatingcanbemixedandpreparedwithrotationaldeviceslikedissolver,butterflymixerorplanetarymixer.Expancelmicrospheresareeasilydispersedandcanbeaddedtothemixtureasthelastcomponent.
25
Application
Exteriorroofsandwallsofhouses,buildings,industrialfacilitiesandwarehousescanbeprotectedbythermalinsulationcoatings.Itcanbeusedonsurfaceslikeconcrete,woodandmetalsheets.
Itisrecommendedtoapplyalayerwithadrythicknessof1.0to1.5mmtoachieveasufficientinsulation.Theinsulationcoatingiseasytoapplywitharoller,brushorbyspraying.
High PVC-value
Expancelcontributeswithalargevolumetothecoating.ThebinderdemandofExpancelislowerbyvolumecomparedtoconventionalmineralfillers.Thespecificsurfaceoftheroundparticlesissmall.
Thermal Conductivity and Thermal Insulation
ThethermalconductivityandinsulationareinfluencedbytheadditionofExpancelandthecontentofmineralfiller.
AmineralfillerlikeCaCO3willincreasethethermalconductivity.Expancel,withtheporousstructureinthecoating,willreducethethermalconductivityandimprovethermalinsulation.
10
Further Properties
Theexpandedmicrospheresareclosedcells.Thiswillimprovethewaterresistanceofacoating.
PaintswithExpancelhaveahigherwatervapourpermeabilitythancorrespondingstandardpaints.
26
TheUVcrosslinkingtechnologyoftheacrylicbinderhasbeenoptimisedtoguaranteealowdirtpick-upperformance.Duetothehighvolumesolidsofacoatingwithexpandedmicrospheres,thedryingtimeisshortened.
ThehighvolumecontributionfromthemicrosphereswillgivealowdensityandalowVOC-emission(g/l)oftheinsulationcoating.
Guiding formulation
BaseCoating Weight Volume g % cc %Grind Water 70.0 9.3 70.0 11.5 Orotan731A 10.7 1.4 9.7 1.6 TritonDF-16 2.2 0.3 2.1 0.3 FoamasterNXZ 3.0 0.4 3.3 0.6 Propyleneglycol 18.0 2.4 17.4 2.9 TioxideTR92 80.0 10.7 20.0 3.3 Durcal5 100.0 13.3 36.4 5.9Premix FoamasterNXZ 3.5 0.5 3.9 0.7 Water 13.0 1.7 13.0 2.1Let down Elastene404 419.0 55.9 402.9 66.2 AcrysolRM-8W 20.0 2.7 19.2 3.2Premix Water 4.6 0.6 4.6 0.8 DMAEDimetylaminoethanol 0.7 0.1 0.8 0.1 AcrysolASE-60 5.3 0.7 5.0 0.8
Totals 750.0 100.0 608.3 100.0
1127
AdditionofExpancel921WE40d24 Weight Volume g % cc % BaseCoating 307.5 89.4 249.4 57.4 Expancel921WE40d24 36.5 10.6 184.9 42.6 Drymicrospheres 3.7 1.1 152.1 35.0 Waterfrommicrospheres 32.9 9.5 32.9 7.6 Totals 344.0 100.0 434.3 100.0
Properties % Pigmentvolumeconcentration % 63.7 Volumesolids % 67.7 Weightsolids % 60.0 Density g/cm3
0.80 Viscosity(Brookfield,spindle5/6rpm) mPas 55000-60000 Viscosity(Brookfield,spindle5/3rpm) mPas 65000-70000
AdditionofExpancel920DET40d25 Weight Volume g % cc % BaseCoating 307.5 89.3 249.4 57.4 Expancel920DET40d25 3.8 1.1 152.0 35.0 FreeWater 33.0 9.6 33.0 7.6 Totals 344.2 100.0 434.4 100.0
Properties % Pigmentvolumeconcentration % 63.7 Volumesolids % 67.8 Weightsolids % 60.1 Density g/cm3
0.80 Viscosity(Brookfield,spindle5/6rpm) mPas 50000-55000 Viscosity(Brookfield,spindle5/3rpm) mPas 60000-65000
10
Expancel® Microspheresin Elastic Wall
and Roof Coatings
11
Elasticwallandroofcoatingisahighlyflexibleexteriorcoatingusedoncement,concreteandsimilarmaterials.Itwithstandswater,whichcouldotherwisecausecrackingandfreeze-thawdegradationinthesubstrate.
Thiscoatingshouldalsobeaneffectivebarrierforcarbondioxideandotheracidgasesintheatmospherethatmightotherwiseneutralisethealkalinityofthesubstrate.
Atthesametimethecoatingshouldbepermeableenoughtoequalisethedifferencesinpartialpressureofwatervaporthatappearbetweenthesubstrateandtheexterior.Thecoatingshouldpreservetheelasticityatlowtemperatures.
29
Suitable Expancel Products
Expancelmicrospheresarehighlyelastic,compressibleparticleswithlowspecificsurface,lowbinderdemandandlowwaterabsorptionbyvolume.Theyaregas-tightandretaintheirvolumeandsphericalformduringpreparation.
Expancel461WE40d36isrecommmendedastheprimarygradeforelasticwallandroofcoating;followedby461DET40d25-ifnotpossibletoaddthewaterthat461WE40d36contains.
Ifachlorinefreegradeisrequired,920DET40d25or921WE40d24isrecommended.
Grade 461WE40d36 461DET40d25 921WE40d25 920DET40d25
Appearance MoistenedPowder DryPowder MoistenedPowder DryPowder
Particlesizeaverageµm 30-50 30-50 35-55 35-55
Truedensityactive 36+3 25+3 24+3 25+3MS,kg/m3(lbs/gal)(0.3+0.025) (0.21+0.025) (0.2+0.025) (0.21+0.025)
Solidcontent(%) 15+2 >99 10+1.5 >99
Formulation of elastic wall and roof coating containing Expancel 461 WE 40 d36
TheformulationsbelowaimtobeaguideonhowthemainpropertiesofelasticwallandroofcoatingschangewhenExpancel461WEmicrospheresareincluded.
AddExpancel461WE40d36andremovethesameamountofmineralextender.Thiswillgive
unchangedviscositywhenadding1%byweightof461WE40d36.
Furtheradditionof461WE40d36decreasestheviscosity.Tomaintainthesameviscositylevelwith2%461WE40d36included,afurthersmalladditionofprimarythickenerisnecessary.
IncorporationofExpancel461DET40d25toelasticwallandroofcoatingswillsignificantly
30
Expancel461WE40d36Water Standard Content 1% 2% 90 90 88Orotan73125% 9 9 9TritonCF-10 2 2 2NopcoNXZ 3 3 3AcrysolRM-836.8% 13 13 13Propyleneglocol 16 16 14TioxideRCR-2 76 76 76Durcal5 250 240 230Expancel461WE40d36 -- 10 20Butylcarbitol 11 11 10SkaneM-8 2 2 2NopcoNXZ 3 3 3Acryliccopolymeremulsion,46% 465 465 465AcrysolASE60/Water1:1pH8 60 60 60
Constants and properties
Densityg/cm3(lbs/gal) 1.30(10.8)1.22(10.18)1.14(9.51)Solidcontent,weight% 56.5 55.6 55.0Solidcontent,volume% 41 44 46PVC% 35 43 49
increasetheviscosityandamorecarefulreformulationisnecessarytoachievesuitableconsistency.
ElasticwallandroofcoatingscontainingExpancelmicrospherescanbepreparedbymeansofaclosedlowspeedmixerordissolver.Usevacuumfordeaerationduringthelastpartofthemixing.
Theingredientsaretobeaddedinthesameorderasthetableshows.
Properties of elastic wall and roof coating containing Expancel 461 WE 40 d36
Water absorptionExpancel461WE40d36canreducethewateraborptionofelasticwallandroofcoating.Thewaterabsorption(mg/cm2)isplottedasthefunctionofthefilmthicknessatthreedifferentimmersions
Thepositiveeffectisclearlyshown.Coatingscontainingmicrospheresaremoreresistenttowatercomparedtocorrespondingcoatingwithoutmicrospheres.ThedifferenceinwaterabsorptionbetweenstandardcoatingandcoatingcontainingExpancelincreaseswithincreasingthickness.
Thisisimportantaselasticwallcoatingsareappliedatadrythicknessof1mmormore.
31
6
5
4
3
2
150 200 300250
0%1%
2%
Wat
era
bsor
ptio
nm
g/cm
2
Filmthickness,µm
Waterabsorptionofelasticwallandroofcoatingwithadditionof0to2%Expancel461WE40d36,1dayofimmersion
Water vapor permeabilityStudieshaveshownthatcoatingsincludingExpancel461WE40d36aremorepermeablethancoatingswithoutandthemicrospheressupportthetransportationofwatervapourthroughthematerial.Thetestisperformedbymeansofthecupmethodandthetruepermeabilitycoefficientsarecalculated.
Asthepermeabilitycoefficientsvarywiththefilmthicknessandthereareothersignificantresistancesthanthematerialinthesystem,theinverseofthepermeabilitycoefficientsareplottedagainsttheinverseofthethickness.
Extrapolationtoinfinitethicknesswillgivethetruepermeabilitycoefficientafterinversion.
TheinfluenceofExpancel461WE40d36onthewatervapourpermeabilitywouldprobablybemoreadvantageousduringtheageingofthecoating,asthetransportmechanismofwatervapourturnsfromactivateddiffusiontocapillaryflow.
32
x10-13
5
9
8
7
0% 2%1%
The
perm
eabi
lity
coef
ficie
nt
AdditionofExpancel461WE40d36
Truepermeabilitycoefficientkgnm/snm2nPaofelasticwallandroofcoatingwithadditionof0to2%Expancel461WE40d36
Low temperature flexibilityAccordingtotestmethodASTMD-1043,thelowtemperatureflexibilityofelasticwallandroofcoatingisnotaffectedbytheadditionofExpancel461WE40d36.Thedeterminedtemperatures(-28
oCto-29
oC/-18.4
oFto-20.2
oF)
areequalforstandardcoatingandcoatingscontainingExpancel.
Solid content by volumeAdditionofExpancel461WE40d36toelasticwallandroofcoatingswillincreasethesolidcontentbyvolume.Thatwillhelpwiththeformationofthicklayerstowhichthesetypesofcoatingsareapplied.
Tensile strengthTheelongationatbreakofwallandroofcoatingscontainingExpanceldecreasesonlyslightlycomparedtostandard.ThetensilestrengthalsodecreasessomewhatwhenExpancelmicrospheresareadded.Thesampleswerestoredfor10weeksatroomtemperaturebeforetesting.
High PVC-values with addition of Expancel 461 WE 40 d36ThegreatvolumecontributionfrommicrosphereswillresultinhighPVC-values,whichisquitemisleading,asExpancel461WE40d36consistsofhollowtightparticleswithalargevoidvolumethathasnodemandofbinder.
Stain resistanceTheelasticwallandroofcoatingisbasedonanacrylicco-polymeremulsion,whichisreticulableonsurfaceatthepresenceofnaturallight.Thereticulationprovidesahighstainresistance,whichismaintainedwhenExpancel461WE40d36isincluded.
33
Tensilestrength,MPa
5
9
8
7
0% 2%1%Elongation,%
Tensilestrengthofelasticwallandroofcoating(ISOR-527II)withadditionof0-2%Expancel461WE40d36.0%
1%2%
Other Acrylic Emulsions
Expancelmicrospheresgivemoderatechangesinthepropertiesofaformulationincludinganacrylicco-polymeremulsionwithsolidcontentof46%.Othermoreelasticacrylicemulsionswithhighersolidcontentareexpectedtogivethesameresult.BinderemulsionssuitableforthisapplicationarePrimalLT-2949andPrimalEC-3848ER.
Cost Savings
AdditionofExpancel461WE40d36tothistypeofcoatingwillgivepossibilitiesformaterialcostsavingsbyvolme.Byusing1%461WE40d36,anapproximatecostsavingwouldbe4-5%.
Correspondingapproximatecostsavingusing2%microspheresis8-9%.
34
Properties
ExpancelAddition 1% 2% 3%Waterabsorptionmg/cm2250µmdryfilmDays of immersion 1: 5.2 4.0 3.5 5: 4.6 3.8 3.3 15: 4.2 3.4 3.1Truepermeabilitycoefficientkgxm/m2nsnPa: 7.51013 8.81013 9.61013
Tensile strength MPA ISO R-537 II, +23oC (+73.4
oF)
Atmaximumstress 1.5 1.4 1.3Atbreak 1.4 1.3 1.1Elongation %Atmaximumstress 240 200 200Atbreak 390 370 330Elasticelongation 390 370 330
Chemical Description SupplierOrotan731 Dispersant Rohm&HaasTritonCF-10 Surfactant Rohm&HaasNopcoNXZ Defoamer Henkel-NopkoAcrysolRM-8 Thickener Rohm&HaasTioxideRCR-2 Titaniumdioxide TioxideDurcal5 Calciumcarbonate OmyaButylcarbitol Coalescent NotspecifiedSkaneM-8 Biocide Rohm&HaasAcrysolASE60 Thickener Rohm&HaasAcryliccopolymeremulsion Binder Rohm&Haas
Rawmaterialusedinsuggestedstartingformulation
35
10
Expancel® MicrospheresWaterborne Printing Inks
11
PrintinginkscontainingExpancelmicrospheresareformulatedtoproducethree-dimensionalprintsontextiles,wallpaper,paper,etc.Itcanalsobeusedtoachieveavelvetlookorothersurfaceeffect.
Thethree-dimensionaleffectisachievedbyheatingtheprinttoatemperatureatwhichthemicrospheresexpandandwhichcausesthebindertocrosslink.
Manyofthecommerciallyavailableprintinginksarealsosuitableforexpandableprintinginks.
FormulationBasicformulations,knownbyexperiencedprintersandinkmanufacturers,mayneedtobeslightlyadjustedduetotheadditionofmicrospherestoproduceraisedprintsonvarioussubstrates.
Abasicrecipecouldbe:
Expancel(dryweight)0-20partsperhundredBinder(s)40-60partsperhundredThickener2-35partsperhundred
Asaguide,theamountofdrybindershouldbeatleastthreetimestheamountofdrymicrospheresinordertogivegoodresistancetoabrasion.
However,themechanicalpropertiesofthebinderandalsotheexpansioncapacityofthegradeofExpancelhaveaninfluenceontheresistancetoabrasion.
37
Mixing Equipment
Nospecialmixingequipmentisrequired.
Bestresultsareachieved,however,withahomogenizersuchasaSilversonmixer.
Pigmentation
Printsmadefromunpigmentedinkhaveawhitesemi-opaqueappearance.
Byaddingupto10%byweightoftitaniumwhite,completelyopaquewhiteprintswillbeachieved.
Forcolouredprinting,addupto8%micro-pigmentdispersionsofnon-ioniccolours.
Components of the Printing Ink
BinderThebindershouldbehighlyelastic,giveagoodadhesiontothefabricandhavegoodwettensilestrength.
MicrospheresTherearedifferentgradesofExpancelfromwhichtochoosedependingontheheatingconditions:
642WU40- generalpurpose031WUF40- verygoodexpansion atlowtemperatures,inert,white007WUF40- verygoodexpansionatslightly highertemperatures,inert,white920WUF40- goodexpansionatveryhigh temperatures,inert,white.
Typicaldosagelevelsofmicrospheresare10-17%(dryweight)ofthetotalweightoftheformulation.Thegreatertheamountofmicrospheresthegreatertheloftoftheprint.
ExpancelWUFgradesarespecialgradeswhichcanbeusedinformulationswheretherheologicalstabilityisaproblem.ComparedtootherExpancelgrades,thedosageof031WUF40and007WUF40canbereducedby30-50%.
ThickenerThethickenershouldgiveashortbutteryrheology.Asuitablethickeneris,forexample,PrintofixThickernDSLiquid.
Auxiliary chemicalsGlycerineisahygroscopicagentandisaddedtopreventskinningandcloggingofscreens.FoamasterENA-515isaddedasadefoamer.WaterisaddedtocompensateforthevaryingsolidcontentofExpancel.
Inthefollowingformulationtheamountofthebinder(assolids)is26%byweight.Ifthispercentageisraised,anincreaseinstrengthand,possibly,inheightwillbegainedbutatthesametimetheinkdriesfaster,whichmaycausecloggingofthescreen.
TextilesIn a printing ink for textiles,
Expancel can help achieve effects such as a velvety look, puff effect
and the resemblance of embroidery.
38
Fixation
Duringfixation,thefollowingprocessestakeplace:
-dryingofthepaint-expansionofthemicrospheres-crosslinking/curingofthebinder
Thefixationtakesplaceindirectconnectionwiththeprintingat120-160
oC(248-320
oF).
Thetemperaturedependsonmicrospheregrade,substrate,typeofbinder,degreeofdepositandcuringoventobeused.
Fixationtakes1-3minutes,butcouldbeprolongedifacompletedrying/curingisnotobtainedwithinthistime.Theoptimumdrying/curingconditionsmaybetestedbytheprinter.
Incaseofmulti-colourprintingtheprintedmaterialisintermittentlydriedatroomtemperatureorupto80
oC(176
oF).
Intheeventofoverheatingand/orifatoolongheatingtimeisused,themicrospheresmaycollapseandbecomediscoloured.
Aninfrareddryermaybeusedinsteadof,orincombinationwith,aheatingoven.Alowertemperatureand/orashortertimeisthenrequired.
Textile Formulation
Amount in gPrimalECO-8(45.5%) 603.3Expancel642WU40(65%) 154-261.5Glycerine(100%) 40FoamasterENA-515(50%) 5H2O 174.9-67.4NH3(25%) approx3.5PrintofixThick,DSLiquid 19.3Total 1000g
Theviscosityoftheprintinginktendstoincreasewhenstored.
Procedure
Allingredients,exceptthickenerandammonia,aremixedusingahomogenisertoattainauniformmixture.AmmoniaisaddedtoadjustthemixturetoapHofapproximately8.5.Thethickenerisaddedtothemixtureduringstirring.Continuestirringuntilthickeningiscompleteandasmoothmixturehasbeenobtained.
Printing
Screenprintingandgravureprintingaresuitableapplicationtechniquesforexpandableprintinginks.Thethree-dimensionaleffectsbecomemostapparentwithaheavydeposit.
39
Components of the Printing Ink
BinderImportantpropertiesofthebinderareadhesionandresistancetoabrasion.Ahardbindercangivethedesiredresistancetoabrasionwhileaverysoft(andsticky)bindercanimprovetheadhesion.
AsuitablehardbinderisPrimalECO-16orequivalent.AsuitablesoftbinderisMowilithDM105orequivalent.
MicrospheresThereareseveralgradesofExpancelthataresuitableforwallpapers:
642WU40- generalpurpose031WUF40- verygoodexpansion atlowtemperatures,inert,white007WUF40- verygoodexpansionatslightly highertemperatures,inert,white920WUF40- goodexpansionatveryhigh temperatures,inert,white
TheamountofExpancelshouldbe1-15%(dryweight)ofthetotalweightoftheformulation.Thegreatertheamountofmicrospheresthegreatertheloftoftheprint.
Expancel031WUF40,007WUF40and920WUF40arespecialgradeswhichcanbeusedinformulationswheretherheologicalstabilityisaproblem.ComparedtootherExpancelgrades,thedosageof031WUF40and007WUF40canbereducedby30-50%.
ThickenerThethickenershouldgiveapseudoplasticrheology.Thiswillproducealowviscosityathighshearratesandwillallowprintingathighspeeds.Atthesametime,theviscositywillbehighatlowshearrates,preventingtheinkfromflowingafterprinting.
AsuitablethickenerisAcrysolRM-8;LyoprintPTXNisalsosuitableifamorepronouncedpseudoplasticityisdesired.
WallpaperFormulations suitable for printing
on wallpaper have been developed to achieve 3D and matting effects.
40
Ifpigmentsareaddedasadrypowder,theyshouldbeaddedandproperlydispersedin,forexample,thebindersbeforethemicrospheresareadded.Thereasonisthatitisgenerallymoredifficulttodispersepigmentsthanmicrospheres.
Itmightbenecessarytoaddadispersantinordertoobtaingooddispersionofthepigment.
Ifthepigmentisaddedasadispersionitcanbeaddedatanypoint.
Viscosity
Theprintinginkexhibitsapseudoplasticflowieitsviscositydecreaseswithincreasingshearrates.Regulateviscositybyusingmoreorlessthickenerintheformulation.
Pot Life
Storagedurabilityoftheaboveformulationisapproximatelyfourmonthswhenkeptinclosedcontainers.Apreservativecanbeaddedinordertopreventthegrowthofbacteriaandfungi.
Laboratorytestshavebeencarriedoutwithgoodresultsattheadditionof0.1-0.2%ActicideSPX.
Hydroscoping AgentGlycerineorpropyleneglycolcanbeusedtopreventskinningandcloggingofscreens.
DefoamerThedefoamerpreventsformationoffoamduringmixing.AsuitabledefoamerisFoamasterENA-515orequivalent.
WaterWaterisaddedtocompensateforthevaryingsolidcontentofExpancel.
Preparation
Micropheres,binders,hygroscopicagentanddefoamersaremixed.Bymeansofahighspeedmixer(homogeniser)themicrospheresarecompletelydispersedinthemixture.Caremustbetaken,however,thatthemixingdoesnottaketoolongsincedevelopedheatathighshearratesmaycauseprematureexpansionofthemicrospheres.
Thethickenerisaddedwhilethemixtureisbeingstirred.Continueagitationuntilasmoothmixtureisobtained.
Waterisaddedeitherasthelastcomponentorinthepre-mixtureofmicrospheres,binders,hygroscopicagentanddefoamer.
41
Screen Printing
Thethreedimensionaleffectsbecomemostapparentwithaheavydeposit.Thisisachievedbymeansofacoarsescreen,60-85mesh(24-34threadspercm).Byusingfinerscreensie100-125(40-50threads/cm)mesh,alowerdepositand,thereby,finepatternsandsharpcontours,areobtained.Itisrecommendedtofiltertheprintinginkbeforeapplicationtopreventcloggingofthescreen.
Drying
Drying,expansionandcuringarepreferablydoneimmediatelyafterprintingfor0.5-2minutes.Incaseofmulti-colourprinting,theprintedmaterialisintermittentlydriedat20-85
oC(68-185
oF).
Iftheprintisdriedbeforeexpansionthiswillproduceprintswithasmoothsurface.Iftheprintisexpandedwithoutdryingthiswillproduceprintswitharoughersurface.
Expansion and Curing
Thesuitabletemperatureforexpansionandcuringdependsonthemicrospheregradeaswellastheweightofthesubstrateandthedepositandmaybesetat120-180
oC(248-356
oF).
Theprintsthatwereusedtoproducetheexpansioncurvespresentedweredriedatroomtemperaturebeforetheywereexpandedinahotairoven.Theseexpansioncurvesmighthelpinfindingsuitableexpansiontimesandtemperatures.
Aninfrareddryermaybeusedinsteadoforincombinationwithaheatingoven.Alowertemperatureand/orashortertimeisthenrequired.
Intheeventofoverheatingand/orusingatoolongheatingtime,themicrospheresmaycollapseandbecomediscoloured.
Therecommendeddrying/curingconditionsmaybeadjustedbytheprinterdependingonsubstrate,degreeofdepositandthecuringoventobeused.
42
Effect on surface roughness when drying before expansionThesurfaceofaprintthatisheatedandexpandedimmediatelyafterprintingmaybecomesomewhatroughbecauseofwatervapour.
Ontheotherhand,iftheprintisfirstdriedatatemperaturewhichistoolowtostarttheexpansionthesurfaceoftheexpandedprintwillbesmoother.
Surface Modification
Byusingmicrosphereswithdifferentparticlesizes,thelookandfeeloftheprintedsurfacecanbemodified.
43
Expancel920WUF40
Expancel930DU120
Printdriedbeforeexpansion,SEM20x
Printnotdriedbeforeexpansion,SEM20x
Wallpaper Formulations
WallpaperformulationwithExpancel642WU40usingMowilithDM105andPrimalECO-16asbindersandLyoprintPTXNasthickener.
Solids Amount % (g) (oz)MowilithDM105 55.0 407.8 14.4PrimalECO16 45.5 335.6 11.8Expancel642WU40 67.5 88.9 3.13Glycerine 100.0 50.0 1.76FoamasterENA-515 50.0 8.0 0.28LyoprintPTXN 90.0 10.0 0.35Water 0.0 99.7 3.52Total 50.01000.0 35.3
Partofnon-volatilesbeingbinders:75.4%Partofnon-volatilesbeingmicrospheres:12%Binder/microspheres(solids/solids):6.28
44
Expansionfactor[x]after60sexpansion
Temperature[oC]
45
Suppliers of Chemicals
Chemical Agent SupplierPrimalECO-8 Acrylicemulsionbinder RohmandHaas
PrimalECO-16 Methylmethacrylate/ethlyacrylatemulsionbinder RohmandHaas
MowilithDM105 Vinylacetate/ethylenecopolymerdispersionbinder CelaneseEmulsions
PrintofixThickenerDSLiquid Syntheticthickenerbasedonammoniumpolyacrylate Clariant
LyoprintPT-XN Acrylicpolymerdispersion Huntsman
AcrysolRM-8 Polyurethanethickener RohmandHaas
FoamasterENA-515 Mineraloilbaseddefoamer Cognis
ActicideSPX Preservative ThorChemicals
ParticleSize TrueDensity SolventExpancel µmD(0.5) kg/m3 Resistance
551DE40d42 30-50 42+4 3461DE20d70 15-25 70+6 4461DE40d60 20-40 60+5 4461DET40d25 35-55 25+3 4920DE40d30 35-55 30+3 5920DET40d25 35-55 25+3 5
Specification
ProductSpecificationforExpancel®microspheres
Expancel DEDryExpandedMicrospheres
46
Est.ParticleSize Solid TrueDensity True SolventExpancel µmD(0.5) Content kg/m3 Volume Resistance
461WE20d36 20-30 15+2 36+4 4.2+0.45 3461WE40d36 30-50 15+2 36+4 4.2+0.45 3921WE40d24 35-55 10+1.5 24+3 4.2+0.45 5
Expancel WEWetExpandedMicrospheres
Expancel DUDryUnexpandedMicrospheres
ParticleSize ThermomechanicalAnalysis SolventExpancel µmD(0.5) Tstart
oC Tmax
oC Densitykg/m3 Resistance
551DU40 10-16 95-100 139-147 <17 3461DU20 6-9 100-106 137-145 <30 4461DU40 9-15 98-104 142-150 <20 4051DU40 9-15 108-113 142-151 <25 4031DU40 10-16 80-95 120-135 <12 3053DU40 10-16 96-103 138-146 <20 3093DU120 28-38 120-130 188-203 <6.5 5909DU80 18-24 120-130 175-190 <10 5920DU40 10-16 123-133 168-178 <17 5920DU80 18-24 123-133 180-195 <14 5920DU120 28-38 122-132 194-206 <14 5930DU120 28-38 122-132 191-204 <6.5 5950DU80 18-24 138-148 188-200 <12 5951DU120 28-38 133-143 190-205 <9 5
47
ParticleSizeD(0.5): 28-38µm ThermomechanicalAnalysis: Tstart 122-132
oC
Tmax 194-206oC
TMA-density <14kg/m3
ResidualSubstances:Acrylonitrile <30mg/kgMethacrylonitrile <100mg/kgSodium2-cyanoethanesulfonate <200mg/kgSulfite <2000mg/kg
Expancel FG92 DUX 120DryUnexpandedMicrospheres
Expancel MBMasterbatchwithUnexpandedMicrospheres
Heightof BulkDensityExpancel Grade Concentration Carrier Foaming(mm) (g/l)
920MB120 920-120 65+1 EVA* 90-140 400-500 (200
oC)
930MB120 930-120 65+1 EVA* 100-150 400-500 (200
oC)
950MB80 950-80 65+1 EVA* 90-130 400-500 (210
oC)
951MB120 951-120 65+1 EVA* 100-150 400-500 (210
oC)
EVA*-Co-polymerofethylenevinylacetate
48
Expancel WUWetUnexpandedMicrospheres
DryContent ParticleSize ThermomechanicalAnalysis Expancel % µmD(0.5) Tstart
oC Tmax
oC Densitykg/m3
551WU40 71+2.5 10-16 95-100 139-147 <17461WU20 68+2.5 6-9 100-106 137-145 <30461WU40 68+2.5 9-15 98-104 142-150 <20007WU40 71+2.5 10-16 91-99 138-143 <15031WUF40 76+2.5 10-16 80-95 120-135 <12053WU40 71+2.5 10-16 96-103 138-146 <20920WUF40 71+2.5 10-16 123-133 170-180 <17
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Boud Minerals ABHåkantorpsvägen109SE-26391HöganäsSwedenTel:+4642333741Fax:+4642333829Web:www.boud.comEmail:[email protected]
Boud Minerals LimitedWestBankSuttonBridgeLincolnshirePE129URUKTel:+44(0)1406351988Fax:+44(0)1406350897Web:www.boud.comEmail:[email protected] B