1、Designation: D6131 17Standard 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
2、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.T
3、his 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 theresp
4、onsibility 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-iz
5、ation 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, Materia
6、ls, 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 Col
7、or-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 diox
8、ide 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 a
9、re 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
10、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 preparin
11、g 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
12、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 readabi
13、lity of 0.01 g andresolution of 0.02 g6.2 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.Cur
14、rent 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 Annua
15、l 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 re
16、cognized 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.16.3 Drawdown Bars, capable of applying a coating typically15.
17、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-tometer meeting the requirements o
18、f Practice E1164 having aspectral range of at least 400 to 700 nm at 10 nm intervals andhaving a measuring port ideally 25 mm in size, and measuringTotal:Normal (di:0), sometimes called SPIN or SIN.Alternatively, but less desirably, one may utilize a smallermeasuring aperture and measuring geometry
19、Diffuse:Normal(de:0), 45:Normal (45:0) or (0:45), or a spectro-colorimeter,or tristimulus colorimeter, in descending order of desirability.7. Procedure7.1 Disperse both reference and test pigment separately intoa liquid medium in a formula that emulates the desired end usefor the pigment by a disper
20、sion method that as closely aspossible simulates the actual production method of dispersion.7.2 Draw down the reference white sample and the testwhite sample side-by-side on a coated black and white draw-down card.7.3 Dry the drawdown by air drying, warm air circulation,or microwave drying.7.4 Inspe
21、ct both sides of the drawdown visually to assurethat both coatings are at complete hide. If either specimen isnot at complete hide, terminate the test.7.5 Measure both specimens on the drawdown over thewhite portion of the drawdown card and obtain the D65-10tristimulus values of both specimens eithe
22、r directly from theinstrument software, or by tristimulus integration following themethods of Practice E308. Make the measurement followingthe appropriate instructions in Test Methods E1331, E1347,orE1349 depending upon the geometry selected.8. Calculation8.1 Calculate the yellowness index of each s
23、pecimen fromEq 1:YI 5100 1.0313 X 2 1.1498 Z!Y(1)where X, Y, and Z are the D65-10 tristimulus values of thespecimen and YI is the yellowness index and the test result.8.2 Increasingly positive values of YI indicate increasingyellowness and increasingly negative values indicate increas-ing blueness.9
24、. Exceptions9.1 It is presumed that the user knows the yellowness indexof the standard material, and its presence is provided in eachtest as an anchor for the scale of blueness to yellowness.However, since the test will most often be performed for thepurpose of assessing the yellowness property of a
25、n unknownmaterial rather than for quality control it is permissible to runthe test without the standard component. This is especiallyuseful where the test results are for internal company consump-tion only. If data may be distributed outside the performinglaboratory, it ought to include the standard
26、 component.10. Report10.1 Report the following information:10.1.1 The type and identification of the test pigment andreference standard pigment,10.1.2 The mass ratio of pigment to vehicle,10.1.3 The measuring instrument used, and its geometry,10.1.4 The instrument readings in the form of tristimulus
27、values of the standard and of the trial, and10.1.5 The yellowness index.11. Precision and Bias11.1 PrecisionThe precision statement is under develop-ment by the Subcommittee and will be available in July 2018.11.2 BiasBias cannot be determined because there is nostandard reference material for this
28、test method.12. Keywords12.1 tint undertone; titanium dioxide pigmentASTM 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 an
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