ASTM D5326-1994a(2002) Standard Test Method for Color Development in Tinted Latex Paints《染色胶乳涂料中颜色显现的标准试验方法》.pdf

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1、Designation: D 5326 94a (Reapproved 2002)Standard Test Method forColor Development in Tinted Latex Paints1This standard is issued under the fixed designation D 5326; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last

2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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

3、 the 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 the standard. The values given in parentheses are forinformation only.1.3 This standard does not purport to add

4、ress 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:D 16 Terminolo

5、gy for Paint, Related Coatings, Materials,and Applications2D 2244 Practice for Calculation of Color Tolerances andColor Differences from Instrumentally Measured ColorCoordinates2D 3924 Specification for Standard Environment for Condi-tioning and Testing Paint, Varnish, Lacquer, and RelatedMaterials2

6、D 3925 Practice for Sampling Liquid Paints and RelatedPigmented Coatings2E 284 Terminology of Appearance2E 1164 Practice for Obtaining Spectrometric Data forObject-Color Evaluation2E 1331 Test Method for Reflectance Factor and Color bySpectrophotometry Using Hemispherical Geometry2E 1345 Practice fo

7、r Reducing the Effect of Variability ofColor Measurement by the Use of Multiple Measurements2E 1347 Test Method for Color and Color-Difference Mea-surement by Tristimulus (Filter) Colorimetry2E 1349 Test Method for Reflectance Factor and Color bySpectrophotometry Using Bidirectional Geometry23. Term

8、inology3.1 Definitions:3.1.1 color developmentthe extent to which the coloranthas achieved its full tinting potential, as evidenced by the colorchange or lack thereof, when the tinted paint is subjected tovery strong shear stress.3.1.2 tintabilitythe capability of a white or tint base paintto accept

9、 various colorants, as evidenced by the color devel-opment in the mixture.3.1.2.1 DiscussionSometimes called “color acceptance”.3.2 See Terminology D 16, E 284, and the Paint/CoatingsDictionary3for definitions of other terms used in this testmethod.4. Summary of Test Method4.1 The test paint is appl

10、ied 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 difference between the drawdownand sheared areas after dryi

11、ng, 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, the paint, or both. This will result in poor colordevelop

12、ment, 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 colorant, if any, and produces a color variationbetween the un

13、sheared 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 betterthe color development and vice versa. Color difference values1T

14、his test 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 Sept. 15, 1994. Published November 1994. Originallypublished as D 5326 9

15、2. Last previous edition D 5326 94.2Annual Book of ASTM Standards, Vol 06.01.3Available from Federation of Societies for Coatings Technology (FSCT), 492Norristown Rd., Blue Bell, PA 19422-2350.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United

16、 States.obtained 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 can be a problem in thepro

17、duction 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 paint is subjected at differe

18、nt 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 case, shear dispersioncan

19、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 paintproperty, for the measu

20、rement 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 Test Charts, black and white

21、 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, plastic disposable type.6.6

22、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 D 2244 and TerminologyE 284.77. Sampling and Conditioning7.1 Take a pint (500 mL) sample of the materia

23、l in accor-dance with Practice D 3925.7.2 Adjust or allow the sample to come to room temperatureas defined in Specification D 3924 (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 or otherwiseundispers

24、ed 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 evenly onto the chart i

25、n 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 and distribute an addi

26、tional 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 the container to rem

27、ove 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 period, brush over t

28、he 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 opposite directions f

29、ollowed 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 brush so as to mainta

30、in 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 section along with thed

31、rawdown 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 areas that might have oc

32、curred 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 D 2244. Modern color differencemeters give DE*abdirectly without need for c

33、alculations.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 Company; 15 WhitneyRoad; M

34、ahwah, 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 that measures the C

35、IE 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 instrumentation andother factors:

36、Practice E 1164, Test Method E 1331, Practice E 1345, Test MethodsE 1347, E 1349.D 5326 94a (2002)29.1.1 CIELAB Color difference DE*ab, between drawdownand brushout,9.1.2 A general description of the color and the type of paintbeing tested, and9.1.3 Specific names and sources of commercial productsb

37、eing 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 drawdown applicat

38、orand 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 thefollowing c

39、riteria 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 the test applic

40、ations 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 discarded beca

41、use 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 normal Gaus-

42、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 based on either

43、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 reproducibility stated

44、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 rights asserted

45、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

46、responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive ca

47、reful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM Internatio

48、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).8Supporting data are available from ASTM International Headquarters. RequestRR: D01-1079.D 5326 94a (2002)3