ASTM_D_185_-_07_2012.pdf

Designation:D18507(Reapproved 2012)Standard Test Methods forCoarse Particles in Pigments1This standard is issued under the fixed designation D185;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 Department of Defense.1.Scope1.1 These test methods cover the determination of theamount of coarse particles in dry pigments.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E11 Specification for Woven Wire Test Sieve Cloth and TestSieves3.Significance and Use3.1 In production of paints,smoothness of the paint film isof paramount importance.Agglomerates or coarse particleslarger than 45 m are difficult to disperse and may preventobtaining a smooth film.These test methods are a valuablequality control test for grading raw materials.4.Apparatus4.1 The apparatus shall consist of a 200-mm(8-in.)45-m(No.325)sieve conforming to Specification E11.An 8-in.45-m sieve for comparison purposes should be retained in thelaboratory as a reference standard.Whenever a new sieve issecured,a practical test of its accuracy should be made byrunning on it and on the reference standard sieve a comparisontest,using a pigment that has a considerable amount of coarseparticles.A reserve stock of such a pigment should be kept forthis purpose.5.Procedure for Insoluble Dry Pigments,Except MetallicAluminum and Bronze Powders5.1 Weigh approximately 100 g of a pigment specimen tothe nearest 0.1 g on an analytical balance.Wet the sieve on bothsides with water and transfer the pigment to the sieve.5.2 Hold the sieve under a tap delivering about 300 to 500mL of the wash liquid(water)per minute.Slightly shake thesieve and move the stream of water around on the pigment inthe sieve to get the pigment to pass through the sieve.Use asoft camel-hair brush to help the pigment wet out and passthrough the sieve.If the sieve is held at a slight angle so thatthe pigment gradually collects at one edge during the washingprocess,and then rotated,the pigment may be brushed outrapidly,with no risk of clogging the sieve.Continue the waterrinsing and brushing until no more pigment is passing throughthe sieve.This can be checked by tilting the sieve andinspecting the water passing through for pigment.5.3 When pigment is no longer passing through the sieve,adjust the tap to a slow stream of water.Tilt the sieve and flowwater through to collect the retained material in one place nearthe edge.Then tilt the sieve more so that the slow flow of waterstrikes the bottom of the screen and rinses out completely theretained particles into a 100 mL beaker.A squirt bottle mayhelp with this transfer.5.4 Allow the pigment to settle and then decant as muchwater as possible without losing pigment.5.5 Place the beaker in a 105 6 2C oven until the contentsare dry.Take care that no material is lost from the beaker byspattering.After drying,brush the contents of the beaker ontoa piece of weighing paper and weigh to the nearest 0.001 g.Record the weight of retained material.Calculate the percent-age of coarse particles.6.Precision6.1 Precision data are not available at this time.Whenavailable the appropriate precision statements will be added.1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.31 on Pigment Specifications.Current edition approved Nov.1,2012.Published November 2012.Originallyapproved in 1937.Last previous edition approved in 2007 as D185 07.DOI:10.1520/D0185-07R12.2For 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 7.Keywords7.1 agglomerates;coarse particles;pigmentsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.Users of this standard are expressly advised that determination of the validity of any such patent rights,and the riskof infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee