ASTM_D_6131_-_17.pdf

Designation:D613117Standard Test Method forEvaluating the Relative Tint Undertone of Titanium DioxidePigments1This standard is issued under the fixed designation D6131;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 This test method is intended to be used to determine thetint undertone(blue or yellow)of titanium dioxide pigments.This relates to the effective particle size of the pigment1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard 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.Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint,Related Coatings,Materials,andApplicationsE308 Practice for Computing the Colors of Objects by Usingthe CIE SystemE1164 Practice for Obtaining Spectrometric Data for Object-Color EvaluationE1331 Test Method for Reflectance Factor and Color bySpectrophotometry Using Hemispherical GeometryE1347 Test Method for Color and Color-Difference Mea-surement by Tristimulus ColorimetryE1349 Test Method for Reflectance Factor and Color bySpectrophotometry Using Bidirectional(45:0 or 0:45)Geometry3.Terminology3.1 Any special terms used in this test method can be foundin Terminology D16.4.Summary of Test Method4.1 Titanium dioxide pigments are dispersed in a liquidmedium of the users choice by a dispersion method applicableto the users intended end use.Test and reference pigments aretreated identically.The resultant white paints or colorants aredrawn down on white and black cards and read instrumentally.These readings are then used to calculate the yellowness index.5.Significance and Use5.1 This test method allows the user to make a determina-tion of the blueness or yellowness of the tint undertone oftitanium dioxide pigments,versus a reference pigment agreedupon by the parties to the test.This is an important measure oftone,since it gives both a measure of effective particle size,andquick approximation of the blue/yellow undertone that can beexpected when a coating containing the titanium dioxide istinted.5.2 Such matters as the vehicle for preparing the dispersionsand the mechanical method of preparing the dispersion are leftto the user.However,variation in these practices will lead toincreased variance in the results,so users ought to fix theseparameters,in-so-far as is possible,within any one laboratory.This will lead to reduced uncertainty of the results within thatlaboratory,and it is seldom that interlaboratory comparisons ofthis test result is needed.5.3 Each user must decide whether the loss of accuracy inhis measurements due to variation of these parameters isnegligibly small for the purpose for which the data areobtained.6.Apparatus6.1 Balance,electronic scale with readability of 0.01 g andresolution of 0.02 g.6.2 Drawdown Cards,black and white sealed drawdowncharts.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.26 on Optical Properties.Current edition approved Dec.1,2017.Published December 2017.Originallyapproved in 1997.Last previous edition approved in 2012 as D6131 97(2012).DOI:10.1520/D6131-17.2For 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 6.3 Drawdown Bars,capable of applying a coating typically15.25 cm wide.The applicators must be capable of applying200 microns wet film or other wet film thickness as appropri-ate.Bird type applicators are marked in thousandths of an inchat half the actual clearance.6.4 Color Measuring Instrument,a colorimetric spectropho-to