ASTM_D_2196_-_20.pdf

Designation:D219620Standard Test Methods forRheological Properties of Non-Newtonian Materials byRotational Viscometer1This standard is issued under the fixed designation D2196;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 These test methods cover the determination of theapparent viscosity and the shear thinning and thixotropicproperties of non-Newtonian materials in the shear rate rangefrom 0.1 s1to 50 s1using a rotational viscometer operatingin a fluid contained in a 600 mL low form Griffin beaker.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Summary of Test Method2.1 Test Method A consists of determining the apparentviscosity of coatings and related materials by measuring thetorque on a spindle rotating at a constant speed in a 600 mLlow form Griffin beaker.2.2 Test Methods B and C consist of determining the shearthinning and thixotropic(time-dependent)rheological proper-ties of the materials.2The viscosities of these materials aredetermined at a series of prescribed speeds of a rotationalviscometer with a spindle operating in a fluid contained in a600 mL low form Griffin beaker.The agitation of the materialimmediately preceding the viscosity measurements is carefullycontrolled.3.Significance and Use3.1 Test Method A is used for determining the apparentviscosity at a given rotational speed,although viscosities at twoor more speeds give better characterization of a non-Newtonianmaterial than does a single viscosity measurement.3.2 With Test Methods B and C,the extent of shear thinningis indicated by the drop in viscosity with increasing rotationalspeed.The degree of thixotropy is indicated by comparison ofviscosities at increasing and decreasing rotational speeds(TestMethod B),viscosity recovery(Test Method B),or viscositiesbefore and after high shear(combination of Test Methods Band C).The high-shear treatment in Test Method C approxi-mates shearing during paint application.The viscosity behaviormeasured after high shear is indicative of the characteristics ofthe paint soon after application.4.Apparatus4.1 Rotational ViscometerThe essential instrument willhave the following capabilities at a minimum:4.1.1 A drive motor,to apply a unidirectional rotationaldisplacement to the spindle immersed in the specimen forrotational speeds between 0.307 rad/sec and 10.24 rad/sec(0.3r/min and 100 r/min)constant to within 0.1%.4.1.2 A force sensor to measure the torque required to drivethe spindle immersed in the specimen at each of the definedspeed settings to within 0.1%.4.1.3 A coupling shaft,or other means,to transmit therotational displacement from the motor to the spindle.4.1.4 A rotational element,spindle,or tool,such as theshapes shown in Fig.1 to fix the specimen between the spindleand a stationary surface.The protective bracket,which attachesto the viscometer and protects the spindle,provides thestationary surface described in the preceding sentence.NOTE1Each spindle can measure a range of almost four decades inviscosity for the speed settings specified in this method.The spindle isselected so that the measured torque value is between 10%and 100%.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.24 on Physical Properties of Liquid Paints&Paint Materials.Current edition approved Dec.1,2020.Published December 2020.Originallyapproved in 1963.Last previous edition approved in 2018 as D2196 181.DOI:10.1520/D2196-20.2Pierce,P.E.,“Measurement of Rheology of Thixotropic Organic Coatings andResins with the Brookfield Viscometer,”Journal of Paint Technology,Vol 43,No.557,1971,pp.3543.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of Interna