ASTM_D_7394_-_13.pdf

Designation:D739413Standard Practice forRheological Characterization of Architectural Coatingsusing Three Rotational Bench Viscometers1This standard is issued under the fixed designation D7394;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This practice covers a popular industry protocol for therheological characterization of waterborne architectural coat-ings using three commonly used rotational bench viscometers.Each viscometer operates in a different shear rate regime fordetermination of coating viscosity at low shear rate,mid shearrate,and at high shear rate respectively as defined herein.General guidelines are provided for predicting some coatingperformance properties from the viscosity measurementsmade.With appropriate correlations and subsequent modifica-tion of the performance guidelines,this practice has potentialfor characterization of other types of aqueous and non-aqueouscoatings.1.2 The values in common viscosity units(Krebs Units,KUand Poise,P)are to be regarded as standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D562 Test Method for Consistency of Paints MeasuringKrebs Unit(KU)Viscosity Using a Stormer-Type Viscom-eterD869 Test Method for Evaluating Degree of Settling of PaintD1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD1200 Test Method for Viscosity by Ford Viscosity CupD2196 Test Methods for Rheological Properties of Non-Newtonian Materials by Rotational(Brookfield type)ViscometerD2805 Test Method for Hiding Power of Paints by Reflec-tometryD4040 Test Method for Rheological Properties of PastePrinting and Vehicles by the Falling-Rod ViscometerD4062 Test Method for Leveling of Paints by Draw-DownMethodD4287 Test Method for High-Shear Viscosity Using a Cone/Plate ViscometerD4400 Test Method for Sag Resistance of Paints Using aMultinotch ApplicatorD4414 Practice for Measurement of Wet Film Thickness byNotch GagesD4958 Test Method for Comparison of the Brush Drag ofLatex Paints3.Terminology3.1 Definitions:3.1.1 coating rheology,nthe viscosity profile obtained fora fluid coating over a range of shear rates.3.1.2 high-shear viscosity(HSV),nthe viscosity of a fluidcoating at high shear rate(typically measured at 10,000 or12,000 sec-1),and for architectural coatings,it is often referredto as the“ICI”or“brush-drag”viscosity.3.1.3 leveling,nthe ability of a wet coating to flow out toa smooth dry film after application,thereby minimizing oreliminating coating surface irregularities that occur duringbrushing,rolling or spraying(see also Test Method D4062).3.1.4 low-shear viscosity(LSV),nthe viscosity of a coat-ing fluid at low shear rate(typically in the range of 0.001 to1 s-1),often referred to as the“leveling viscosity”or inverselyas the“suspension viscosity.”3.1.5 mid-shear thickener effciency(MSTE),nthe weightof active thickener per unit volume of wet coating required togive the target MSV,commonly expressed as lb activethickener/100 gal wet coating(or in g/L units).3.1.6 mid-shear viscosity(MSV),nthe viscosity of acoating fluid at medium shear rate(typically in the range of 10to 1000 s-1),often referred to as the“consistency”or the“mixing viscosity.”1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.24 on Physical Properties of Liquid Paints and Paint Materials.Current edition approved July 1,2013.Published August 2013.Originallyapproved in 2008.Last previous edition approved in 2008 ad D7394 08.DOI:10.1520/D7394-13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.7 newtonian,na rheological term describing a fluidthat maintains constant viscosity over a range of shear rates(see also Test Method D1200 and Test Method D4040).3.1.8 rheometer,nan instrument capable of continuouslymeasuring fluid viscosity over a range of shear rates or shearstresses,often capable of other types of rheologicaldeterminations,and ideally suited for research and well-defined characterization of fluid rheology.3.1.9 rotational viscometer,nan instrument that uses oneor