Designation:D3360–96StandardTestMethodforParticleSizeDistributionbyHydrometeroftheCommonWhiteExtenderPigments1ThisstandardisissuedunderthefixeddesignationD3360;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationoftheparticle-sizedistributioninthesub-sievesizerangeofthecommonextenderpigmentssuchasaluminumsilicate(kaolinclay),magnesiumsilicate(talc),calciumcarbonate(calciteordolomiteorprecipitatedcalciumcarbonate),andmicapig-ments,andmayalsobeextendedtothedenserprimepigmentssuchasthewhitetitaniumpigments(rutileoranatase)andsimilarmineralpigmentswhenandifsuchinformationisofconcern.Particle-sizedistributionhassignificanceintheevalu-ationofrheologicalandpigmentarypropertiesofpigmentsinpaintandalsomaysometimesbeusedtocharacterizetheidentityorgradeofpigments.1.2SedimentationmethodshavingastheirbasisStoke’slawhavefoundgeneralacceptanceforthispurpose.Resultsareexpressedintermsofequivalentsphericaldiameter(e.s.d.),thediameterofaspherehavingthesamespecificgravityastheparticleinquestionandwhichsettlesatthesamerate.Mostmineralpigmentparticlesaremoreorlessasymmetrical,butdespitedifferencesintherelationshipbetweenequivalentsphericaldiameterandactualdimensions,theresultsofasedimentationparticle-sizeanalysiscanbecorrelatedreadilywithmanypigmentproperties.1.3Procedureslimitedtogravitationalsedimentation2,3,4,5arerelativelyinaccurateforpigmentparticlessmallerthanabout1µme.s.d.,andcentrifugalproceduresmayberequiredforthemuchfinerranges.Nevertheless,thedataobtainedabovethe1-µmlimitationprovideusefulinformation.Thistestmethodisparticularlyapplicabletopigmentsifamajorfractionoftheparticlesfallintherangefromabout15to1.5µm,buthaveatotalparticle-sizerangeofatleasttwodecades.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifa...
