ASTM_D_7867_-_13.pdf

Designation:D786713Standard Test Methods forMeasurement of the Rotational Viscosity of Paints,Inks andRelated Liquid Materials as a Function of Temperature1This standard is issued under the fixed designation D7867;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.Scope1.1 These test methods cover the use of rotational viscom-eters to determine the dependence of apparent viscosity ofpaints,inks and related liquid materials on temperature.Thefirst method uses a standard rotational viscometer with con-centric cylinder geometry running at a fixed rotational speed asthe temperature is increased or decreased.The second methoduses a rotational viscometer with cone and plate geometryrunning at a fixed rotational speed as the temperature isincreased or decreased.The third method uses concentriccylinder or cone/plate geometry operated with a shear rateramp at several discrete temperatures.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard may involve hazardous materials,opera-tions and equipment.This standard does not purport to addressall of the safety concerns,if any,associated with its use.It isthe responsibility of the user of this standard to establishappropriate safety and health practices and determine theapplicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D3925 Practice for Sampling Liquid Paints and RelatedPigmented Coatings3.Terminology3.1 Definitions:3.1.1 apparent viscosity,nviscosity that is not a trueproperty of the fluid,but a variable depending on the shear rate.3.1.2 shear thinning fluidfluid in which the apparentviscosity decreases with increasing shear rate.3.1.3 thixotropic fluid,nfluid whose viscosity is timedependent,that is,its viscosity decreases with the time it issubjected to shear.3.1.4 viscosity,nthe ratio between an applied shear stressto the resulting shear rate(velocity gradient)is defined as thedynamic viscosity;it is a measure of the resistance to flow ofa fluid.4.Summary of Test Methods4.1 Test Method A is run with a viscometer with concentric(coaxial)cylinder capability,either built-in or as an accessorythat allows use of small specimen size(2 to 20 mL).This testis used for measuring apparent viscosity as a function oftemperature at low to medium shear rates.The viscosity-temperature profile of the paint,ink or other material may bedetermined at a fixed shear rate or the viscosity-shear rateprofile may be determined at several discrete temperatures.4.2 Test Method B is accomplished with a viscometer thathas cone/plate test geometry.It is used to measure apparentviscosity as a function of temperature at low to medium shearrates(high shear rates may cause shear heating that interfereswith temperature control).Shear heating is more likely withcone/plate geometry because it permits use of a wider range ofshear rates than does the concentric cylinder instrumentation inMethod A.The upper limit of shear rate will depend on thematerial and its viscosity.The viscosity-temperature profile ofthe paint/coating may be determined at a fixed shear rate or theviscosity-shear rate profile may be determined at severaldiscrete temperatures.The smaller specimen size compared toMethod A permits better temperature control and more rapidcharacterization of the viscosity-temperature profile.4.3 Test Method C is used for determining apparent viscos-ity as a function of a shear rate ramp at multiple discreettemperatures.This method can be used with either coaxialcylinder geometry or cone/plate geometry.A shear rate ramp isdefined and run at a discreet temperature;the viscosity valuesat each shear rate are recorded.The shear rate ramp is thenrepeated at a series of discreet temperatures and the viscosityvalues are measured to characterize the viscosity-temperatureprofile for the sample specimen.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and is the direct responsi-bility of Subcommittee D01.24 on Physical Properties of Liquid Paints&PaintMaterials.Current edition approved June 1,2013.Published July 2013.DOI:10.1520/D7867-13.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.4 Temperature control for Test Methods A,B,and Crequires use of an apparatus that maintains test sample tem-perature within 60.2C of the specified set point.Control towithin 60.1C is preferred if ach