1、Designation: D5326 94a (Reapproved 2009)Standard Test Method forColor Development in Tinted Latex Paints1This standard is issued under the fixed designation D5326; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last re
2、vision. 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 covers a procedure for measuring colordevelopment in tinted latex paints, for the purpose of deter-mining th
3、e efficiency of colorants, the tintability of base paintsand the potential for poor color uniformity of applied paintfilms.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for informatio
4、n onlyand are not considered standard.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 li
5、mitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D16 Terminology for Paint, Related Coatings, Materials,and ApplicationsD2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinatesD3924 Specification for Environment for Condit
6、ioning andTesting Paint, Varnish, Lacquer, and Related MaterialsD3925 Practice for Sampling Liquid Paints and RelatedPigmented CoatingsE284 Terminology of AppearanceE1164 Practice for Obtaining Spectrometric Data forObject-Color EvaluationE1331 Test Method for Reflectance Factor and Color bySpectrop
7、hotometry Using Hemispherical GeometryE1345 Practice for Reducing the Effect of Variability ofColor Measurement by Use of Multiple MeasurementsE1347 Test Method for Color and Color-Difference Mea-surement by Tristimulus ColorimetryE1349 Test Method for Reflectance Factor and Color bySpectrophotometr
8、y Using Bidirectional (45:0 or 0:45)Geometry3. Terminology3.1 Definitions:3.1.1 color development, nthe extent to which the colo-rant has achieved its full tinting potential, as evidenced by thecolor change or lack thereof, when the tinted paint is subjectedto very strong shear stress.3.1.2 tintabil
9、ity, nthe capability of a white or tint basepaint to accept various colorants, as evidenced by the colordevelopment in the mixture.3.1.2.1 DiscussionSometimes called “color acceptance.”3.2 See Terminology D16, E284, and the Paint/CoatingsDictionary3for definitions of other terms used in this testmet
10、hod.4. Summary of Test Method4.1 The test paint is applied by drawing it down on a stripedblack and white sealed chart, at a film thickness sufficient toobtain full hiding.4.2 A portion of the drawdown is subjected to strongshearing forces in a prescribed brushing procedure.4.3 The CIELAB color diff
11、erence between the drawdownand sheared areas after drying, is reported as a measure ofdeficiency in the color development of the test paint.5. Significance and Use5.1 A colorant sometimes fails to disperse completely in abase paint due to poor compatibility, which can be the fault ofthe colorant, th
12、e paint, or both. This will result in poor colordevelopment, which is readily manifested by the commonprocedure of applying the paint with a doctor blade andsubjecting the drawdown to high shear stress by finger-rubbinga small area of the partially dry film. This tends to disperseundeveloped coloran
13、t, if any, and produces a color variationbetween the unsheared and sheared areas of the paint film. Thevariation can be measured colorimetrically to give a numericalcolor difference value that is a measure of the color develop-ment of the original paint, the smaller the difference the better1This te
14、st method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.42 on Architectural Coatings.Current edition approved Dec. 1, 2009. Published December 2009. Originallyapproved in 1992. Last previo
15、us edition approved in 2002 as D5326 94a (2002).DOI: 10.1520/D5326-94AR09.2For 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
16、ASTM website.3Available from Federation of Societies for Coatings Technology (FSCT), 492Norristown Rd., Blue Bell, PA 19422-2350, http:/www.coatingstech.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the color development and vi
17、ce versa. Color difference valuesobtained by finger-rubbing were found to vary widely for thesame as well as among different operators. This test methodestablishes a controlled shear-stress procedure analogous to thefinger rub-up test, but with far better reproducibility.5.2 Poor color development c
18、an be a problem in theproduction of paints, and in their performance in the field. Inproduction it causes a loss of colorant monetary value, andunpredictable tinting results. In field performance it results incolor variations in the applied paint film due to the varyingshear forces to which the pain
19、t is subjected at different stagesor by different modes of application.5.3 Although poor color development is primarily and mostoften related to the colorant portion of a tinted paint, the whitepigment in the base paint can also be poorly developed due toflocculation or other causes. In the latter c
20、ase, shear dispersioncan make the paint film lighter and less colorful, rather than thereverse. Then too, the colorant and the white might both bepoorly developed, and the color change due to shear stresswould then be the combined effect of both.5.4 In any case, color development is an important pai
21、ntproperty, for the measurement of which this test method isintended to provide a generally accepted and reproducible testmethod.6. Apparatus6.1 Film Applicator, 6-in. (150-mm) wide with a clearanceof 10 mils (250 m).46.2 Drawdown PlateA vacuum plate or thick plate glassare both satisfactory.6.3 Tes
22、t Charts, black and white striped, with a sealedsurface, and overall size approximately 812 by 11 in. (245 by280 mm) having a test area of 0.538 ft2(500 cm2).56.4 Paint Brush, 2-in. (50-mm) polyester filaments, 234-in.(70-mm) length out,916-in. (15-mm) thick, with chisel tip.66.5 Syringe, 20 mL, pla
23、stic disposable type.6.6 Force-Draft Oven, maintained at 120 6 2F (50 6 1C).6.7 Reflectometer, using CIE Illuminant C, specular reflec-tion excluded, and capable of measuring CIELAB colorcoordinates as defined in Practice D2244 and TerminologyE284.77. Sampling and Conditioning7.1 Take a pint (500 mL
24、) sample of the material in accor-dance with Practice D3925.7.2 Adjust or allow the sample to come to room temperatureas defined in Specification D3924 (65 to 85F, 18 to 29.5C).8. Procedure8.1 Stir the test paint thoroughly by hand, making sure thatit is completely uniform with no trace of sediment
25、or otherwiseundispersed material. If necessary filter to remove persistentlarge agregates.8.2 Clean the drawdown plate thoroughly and place the testchart on it with the applicator close to the top edge of the chart.8.3 Fill the syringe to the 17-mL mark and from it distribute10 mL of test coating ev
26、enly onto the chart in front of and closeto the applicator, then draw down with a uniform motion.8.4 Without delay cut an approximately 3-in. (75-mm) widepaint strip from the bottom end of the chart and set it aside.8.5 Tape one edge of the remaining portion of the chart ontoa flat support surface a
27、nd distribute an additional 7 mL of testpaint from the syringe evenly over the test area.8.6 Dampen a clean paint brush, shake out the moisturevigorously, then dip the brush to23 of its filament length intothe test paint in a34-filled pint container. Remove the brush,wipe the tip against the edge of
28、 the container to remove thesurplus, then spread the paint evenly over the test area of thechart and allow to dry for 15 6 1 min under room temperatureconditions.8.7 During this drying period keep the wet paint brushwrapped in plastic film to prevent it from drying out.8.8 After the specified drying
29、 period, brush over the paintedarea repeatedly for 2 min 6 10 s. Make sure that each brushstroke fully traverses the painted area and is at a uniform speedsuch that there will be 150 6 5 strokes during the statedbrushing period. Cover the entire area with six successiveparallel strokes in alternate
30、opposite directions followed by thesame in the direction perpendicular to the preceding six,alternating in this way until the specified brushing time iscompleted. During each stroke press the brush down so that athird of the filament length is pressed against the surface of thechart. Manipulate the
31、brush so as to maintain a uniformspreading rate as much as possible during this operation.Complete the brushout by sweeping the tip of the brush overthe painted area to smooth and eliminate brushmarks, and tocompletely obscure the black and white substrate pattern.8.9 Place the completed brushout se
32、ction along with thedrawdown section of the chart in the force-draft oven for oneh 6 2 min.8.10 Remove the two sections from the oven and tape themtogether at the original cut.8.11 Measure the CIELAB color difference DE*abbetweenthe drawdown and the brushout, avoiding measurements onshow-through are
33、as that might have occurred due to persistentdeep brush marks or other deficiency in spreading rate unifor-mity. To obtain DE*abdetermine CIELAB color coordinatesL*a*b*, and from them calculate DE*abin accordance withSections 8 and 9 of Practice D2244. Modern color differencemeters give DE*abdirectl
34、y without need for calculations.9. Report9.1 Report the following information:4A Bird type film applicator, obtainable from most suppliers of paint testequipment, has been found satisfactory for this purpose. Other suitable applicatorsmay be used.5Leneta Form 8K-BW; obtainable from The Leneta Compan
35、y; 15 WhitneyRoad; Mahwah, NJ 07430, was used in the round robins for this standard and foundsatisfactory. An equivalent may be used.6The E-Z Paintr “ONE-V20-90 ONE COATER BRISTLENE” brush has beenfound satisfactory. Available from E-Z Paintr, 4051 S. Iowa Ave., Milwaukee, WI53207.7Any reflectometer
36、 that measures the CIE tristimulus values of opaque surfaceswill be found suitable. Types that provide a direct read-out of color difference DE*abare available, and are particularly desirable for this test method. The followingstandards are applicable to this measurement, depending on instrumentatio
37、n andother factors: Practice E1164, Test Method E1331, Practice E1345, Test MethodsE1347, E1349.D5326 94a (2009)29.1.1 CIELAB Color difference DE*ab, between drawdownand brushout,9.1.2 Ageneral description of the color and the type of paintbeing tested, and9.1.3 Specific names and sources of commerc
38、ial productsbeing tested, paints or colorants or both.10. Precision and Bias10.1 ExperimentalIn an interlaboratory study8of this testmethod one operator in each of five laboratories tested eightlatex paints that varied widely in color and color development,by applying them with a clearance-type draw
39、down applicatorand then subjecting a portion of the drawdown to very highshear stress using a paint brush (see Note 1).10.2 PrecisionThe interlaboratory pooled standard devia-tion, after discarding several outliers (see Note 2), was found tobe 0.43 DE*abwith 21 df. Based on this standard deviation t
40、hefollowing criteria should be used for judging, at the 95 %confidence level, the acceptability of results:10.2.1 ReproducibilityTwo single results obtained by op-erators in different laboratories should be considered suspect ifthey differ by more than 1.3 DE*ab.NOTE 1In the interlaboratory study th
41、e test applications were airdried, but it was established that there is essentially perfect correlationbetween color difference measurements made on air-dried and force-driedpanels.8NOTE 2Results from one laboratory for three of the paints and oneresult from another for one of the same paints were d
42、iscarded because theydiffered significantly from other results for the same materials or becausethe laboratory mean differed significantly from means of all the otherlaboratories.NOTE 3The measurement or determination of tristimulus values usingmodern spectrocolorimeters has been shown to not follow
43、 normal Gaus-sian statistics. Additionally, the calculation of color differences (DE)involves the positive square root of the sum of the squares of thetristimulus differences. The DE values are distributed more like aCHI-squared variable than a normal variable. As a result, statisticalinferences bas
44、ed on either the normal distribution or the Students tdistribution may underestimate the probabilities of repeating or reproduc-ing a given value.10.2.2 RepeatabilityInsufficient data was obtained to di-rectly establish the repeatability of this test, but it should be atleast equal to the reproducib
45、ility stated in 10.2.10.3 BiasThe concept of bias is inapplicable to this testmethod, because there are no independent authoritative values.11. Keywords11.1 color; color development; color uniformity; colorants;tintabilityASTM International takes no position respecting the validity of any patent rig
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