rheological-additives

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1、TECHNICALBACKGROUND/RHEOLOGICALADDITIVES88RheologicalAdditivesTEGO®ViscoPlusTECHNICALBACKGROUND/RHEOLOGICALADDITIVES89PantaRhei–Greekfor”everythingflows“RheologyWhenacertainforceisappliedtheup-–certainlyappliestopaintsandcoat-perplatereachesavelocityvwhichisings.FrommanufacturethroughstorageRheo

2、logy(Greek:rheos=floworrelatedtotheshearstress.andprocessingtodryingorcuringafterstreaming)isthestudyofdeformationapplication,manydifferentdemandsareandflowofsubstances.Variousrheo-Thetwocharacteristicvalues,shearmadeonacoating,relatedtoitsflowlogicalmethodscanbeusedtocharac-stress,andshearrate

3、•,canbederivedproperties.Characteristicswhichareaf-terizecoatings.fromthetwo-platemodel.Theshearfectedinclude:stressisdefinedastheshearforceF[N]ThequantitiesmeasuredinrheologicalpershearareaA[m2].•settlinginvestigationsareforces,deflections•brushdragandvelocities.Viscosity,themostfre-•spattering

4、quentlyusedrheologicalparameter,is•saggingcalculatedfromtheshearrateandthe•flowshearstress.Basicrheologicalparame-tersareexplainedintermsofthetwo-TheshearrateisobtainedfromtheInsolventborneformulationstheflowplatemodel(fig.1).Theupperplateofvelocityv[m/s]andtheplateseparationpropertiescanbecompl

5、etelyregulatedareaAismovableandthelowerplateh[m].viathemolecularweightofthedis-stationary.Theplatesareseparatedbyasolvedbinder.Inwaterborneformula-distancehwhichisfilledwithliquid.tionsthebinderisintheformofdis-persedpolymerparticlessothatregulationoftheflowbehaviorbychangingthemolecularweightis

6、notpossible.Rheologicaladditives(thicken-ers)mustthereforebeusedtoadjusttheflowpropertiesofwaterbornecoatingsandprintinginks.Figure1:Two-platemodelTECHNICALBACKGROUND/RHEOLOGICALADDITIVES90Figure2:EffectofshearrateonapplicationalpropertiesApplicationpropertiesinpaintsandaswater,solventsandminera

7、loils.InFlowbehaviorcanbeshowndiagram-coatingsareassociatedwithdifferentpractice,mostshearablesystemshavematicallyintwoways:asaflowplotorshearrates(fig.2)andtheflowproper-flowpropertieswhichdependontheaviscosityplot.Aflowplo