ASTM_D_1483_-_12.pdf

Designation:D148312Standard Test Method forOil Absorption of Pigments by Gardner-Coleman Method1This standard is issued under the fixed designation D1483;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.Scope*1.1 This test method covers the determination of oil absorp-tion of pigments by the Gardner-Coleman procedure.21.2 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:3D281 Test Method for Oil Absorption of Pigments bySpatula Rub-out3.Summary of Test Method3.1 A soft paste is formed by the dropwise addition oflinseed oil to the gently stirred pigment.The amount of oilrequired to form the paste is used to calculate an oil absorptionvalue.4.Significance and Use4.1 The oil absorption value obtained by this test methodprovides information about the vehicle demand of the pigmentwhen it is used in a pigment paste.Oil absorption values can beused to characterize batches of a given pigment.4.2 This test method differs from Test Method D281 in thatD281 requires a vigorous rubbing action whereas this testmethod involves only a gentle stirring and folding of thepigment.Because the end points are different,the valuesobtained from the two test methods generally differ.5.Apparatus and Materials5.1 Balance,capable of weighing to 0.01 g.5.2 Glass Container,round-bottom,having a capacity of250 mL(12pt),or a low-form 250-mL beaker.5.3 Buret,graduated in 0.1-mL divisions.5.4 Spatula,sharp-edged steel,having a blade 15 or 20 by100 mm(12or34by 4 in.).5.5 Linseed Oil,raw,conforming to the following specifi-cation:Specific Gravity0.926 0.931Boiling Point149CAcid Number3 1Saponification Value185 196Iodine Value170 minimumGardner Color13 maximum6.Procedure6.1 The weight of pigment used should correspond to apigment volume of 3.0 6 0.6 mL.Determine the weightneeded by multiplying 3.0 6 0.6 mL by the specific gravity ofthe pigment being tested.For example,a 20 g specimennormally is used for zinc oxide(3.6 mL 5.6 g/mL=20.2 g).Transfer the amount,weighed to 0.01 g,to the glass container.6.2 Add oil from the buret at the rate of about 1 drop persecond,stirring and“folding”the pigment continuously withthe spatula during the addition.Try to provide dry pigment forthe oil to strike.Do not rub or grind;as the particles of pigmentbecome wetted,they collect in small lumps that graduallycoalesce.As the coalescence proceeds,reduce the rate of oiladdition by at least half.The end point is reached when thelumps,with a rolling action from the spatula,collect into asingle ball or the excess of oil smears the wall of the container.7.Calculation7.1 Calculate the oil absorption,A,as follows:A 5M 30.93P3100(1)1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.24 on Physical Properties of Liquid Paints&Paint Materials.Current edition approved Feb.1,2012.Published February 2012.Originallyapproved in 1957.Last previous edition approved in 2007 as D1483 95(2007).DOI:10.1520/D1483-12.2See Gardner,H.A.and Coleman,R.E.,“Oil Absorption of Pigments,”Scientific Section Circular 85,Paint Manufacturers Assoc.of the United States,February 1920.3For 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 where:M=oil,mL,andP=pigment,g.0.93 represents density of oil(in grams per millilitre).Express as grams of oil per 100 g of pigment.8.Report8.1 Report the oil absorption of the pigment as grams of oilper 100 grams of pigment.9.Precision and Bias9.1 On the basis of an interlaboratory study of this testmethod in which one operator in each of 5 laboratories tested5 pigments with a broad range of oil absorption levels,thewithin-laboratory coefficient of variation was 3.4%at 25 dfand the between-laboratory coefficient of variation was 5.3%at 20 df.Based on these coefficients,the following criteriashould be used to judge the acceptability of results at the 95%confidence level:9.1.1 RepeatabilityTwo res