ASTM_D_3360_-_96.pdf

Designation:D 3360 96Standard Test Method forParticle Size Distribution by Hydrometer of the CommonWhite Extender Pigments1This standard is issued under the fixed designation D 3360;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of theparticle-size distribution in the sub-sieve size range of thecommon extender pigments such as aluminum silicate(kaolinclay),magnesium silicate(talc),calcium carbonate(calcite ordolomite or precipitated calcium carbonate),and mica pig-ments,and may also be extended to the denser prime pigmentssuch as the white titanium pigments(rutile or anatase)andsimilar mineral pigments when and if such information is ofconcern.Particle-size distribution has significance in the evalu-ation of rheological and pigmentary properties of pigments inpaint and also may sometimes be used to characterize theidentity or grade of pigments.1.2 Sedimentation methods having as their basis Stokeslaw have found general acceptance for this purpose.Results areexpressed in terms of equivalent spherical diameter(e.s.d.),thediameter of a sphere having the same specific gravity as theparticle in question and which settles at the same rate.Mostmineral pigment particles are more or less asymmetrical,butdespite differences in the relationship between equivalentspherical diameter and actual dimensions,the results of asedimentation particle-size analysis can be correlated readilywith many pigment properties.1.3 Procedures limited to gravitational sedimentation2,3,4,5are relatively inaccurate for pigment particles smaller thanabout 1 m e.s.d.,and centrifugal procedures may be requiredfor the much finer ranges.Nevertheless,the data obtainedabove the 1-m limitation provide useful information.This testmethod is particularly applicable to pigments if a majorfraction of the particles fall in the range from about 15 to 1.5m,but have a total particle-size range of at least two decades.1.4 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:D 280 Test Methods for Hygroscopic Moisture(and OtherMatter Volatile Under the Test Conditions)in Pigments6D 422 Test Method for Particle-Size Analysis of Soils7D 1193 Specification for Reagent Water8E 100 Specification for ASTM Hydrometers9E 300 Practice for Sampling Industrial Chemicals103.Summary of Test Method3.1 For the determination of particle-size distribution by theapplication of Stokes law to the sedimentation of particulatematerial out of an initially homogeneous suspension,anysystematic set of measurements which permit the determina-tion of the suspension density(that is,the“percent solids”)atsome defined distance beneath the surface of the suspension atsome appropriately selected series of sedimentation time du-rations can be converted to a particle-size distribution.In thisprocedure,the suspension density is estimated at the effectivedistance beneath the suspension surface of the center of gravityof a floating hydrometer observed at a series of convenient timeintervals selected to increase roughly exponentially.NOTE1Any alternative system that provides an equivalent set ofmeasurements(for example,the Andreasen Pipet Method,4or any of theoptical sampling methods based on change in turbidity,light scattering,and light or X-ray absorption,etc.)will also yield a particle-sizedistribution.Methods based on optical measurements,however,are muchless generally applicable because of certain technological limitations toocomplex to be dealt with here.4.Apparatus4.1 Stirring Apparatus,commonly known as a“malted milkmixer,”with a vertical high-speed shaft(approximately 10 0001This test method is under the jurisdiction of ASTM Committee D-1 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.31 on Pigment Specifications.Current edition approved May 10,1996.Published July 1996.Originallypublished as D3360 74.Last previous edition D 3360 80(1989).2Norton,F.H.,and Speil,S.,Journal of the American Ceramic Society,Vol 21,1938,p.89.3Casagrande,A.,“Hydrometer Method for Determination of Fineness Distribu-tion of Soils,”Julius Springer,Berlin,1934.4Andreasen,A.H.M.,“The Evaluation of Ground Materials,”Kolloid Biehefte,Vol 27,1928,p.349.5Lane,Marvin K.“Improved Method for Measuring Particle Size Distributionsby Gravity Sedimentation with a Hydrometer,”A Work Manual by Lane,M.K.,4147 West Byron St.,Chicago,IL 60641.6Annual Book of ASTM Standards,Vol 06.03.7Annual Book of ASTM Standards,Vol