# ASTM D1366-86 (Reapproved 2012)

Designation: D1366 − 86 (Reapproved 2012)Standard Practice forReporting Particle Size Characteristics of Pigments1This standard is issued under the fixed designation D1366; 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 U.S. Department of Defense.1. Scope1.1 This practice for reporting the fineness characteristics ofpigments is designed to apply in most cases where well-knownmethods for determining these particle size characteristics inthe subsieve range are employed, such as microscopic,sedimentation, and turbidimetric methods; and partially toabsorption and permeability methods.1.2 Laminar, plate-like pigments and composite pigmentshaving a definite bimodal distribution are not considered withinthe scope of this practice.1.3 Parameters—The fineness characteristics are reported inthe following three parameters:1.3.1 Particle Size Parameter.1.3.2 Coarseness Parameter—A parameter descriptive ofthe coarseness character of the pigment, making use of alimiting value in the subsieve range similar to that used in thesieve ranges.1.3.3 Dispersion Parameter—A parameter descriptive ofthe uniformity of the particle size distribution.1.4 This standard does not purport to address the safetyproblems, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E20 Practice for Particle Size Analysis of Particulate Sub-stances in the Range of 0.2 to 75 Micrometres by OpticalMicroscopy (Withdrawn 1994)33. Terminology3.1 Definitions:3.1.1 particle size parameter (specific surface diameter,SSD),n—diameter d3used elsewhere in ASTM test methods.This parameter is the same as that frequently reported as“Average Particle Size by Surface Mean,” and “SpecificParticle Size,” and is defined as follows:SSD 5(d3f/(d2f (1)where:SSD = specific surface diameter, µm,d = mean class size, µm, andf = frequency.Therefore the SSD is the diameter of a sphere having thespecific surface characteristic of the pigment. The true specificsurface of all pigments involves a shape factor. Report SSDwhether or not the effect of shape has been considered in thecalculations. Presumably, as the effect of shape is betterunderstood, it will figure more and more in calculationsinvolving particle size, but in the meantime it will of necessitybe ignored in many cases.3.1.2 coarseness parameter (CP), n—that diameter, ex-pressed in micrometres, below which 99.5 % of the pigmentfalls.3.1.3 dispersion parameter (DP), n—the ratio of the mi-crometre size within which 50 % of the pigment lies, to thespecific surface diameter, SSD. The larger the DP number, thegreater the dispersion parameter and the lower the uniformity.Report the dispersion parameter in all cases when a distributioncurve can be prepared from the original data. The dispersionparameter cannot be calculated from data obtained by absorp-tion or permeability methods. Determine as follows:3.1.3.1 Prepare a cumulative-size distribution curve on3-phase log paper, using the vertical axis for the percent fallingbelow the size indicated, and the horizontal axis (log scale) fordiameter in micrometres. Use the upper class limit correspond-ing to the cumulative weight percentage. Subtract the mi-crometre size at 25 % cumulative weight from the micrometresize at 75 %, and multiply the difference by 100 ÷ SSD,asfollows:DP 5 ~µmat75%2µmat25%!/~SSD! 3100 (2)1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.31 on Pigment Specifications.Current edition approved Nov. 1, 2012. Published November 2012. Originallyapproved in 1955. Last previous edition approved in 2007 as D1366 – 86 (2007).DOI: 10.1520/D1366-86R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at service@astm.org. For Annual Book of ASTMStandards volume information, refer to the standard’s Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Significance and Use4.1 This practice is of value (1) to the producer of fineparticles as a means of reporting particle characteristics withrespect to quality control and (2) to the buyer to assure that theparticle size and particle size distribution meet his require-ments.5. Procedure5.1 Particle Size by Microscopical Methods—Proceduresfor determining particle size by microscopical methods aredescribed in Practice E20. When microscopical methods areemployed, report the data in tabular form similar to that shownin Table 1.5.2 Particle Size by Sedimentation Methods—Sedimentationmethods provide data from which may be calculated the meanclass size and percentage by weight for each of these classsizes. Table 2 presents in the second and third columns datanormally obtained by sedimentation methods. Column 3 ofTable 2, which gives the distribution by weight of the classsizes, is identical with the function d3f. Therefore, the d3ffunction in Column 4 equals d3f/d. The fifth column, cumula-tive weight, percent, is obtained from the values in Column 3.5.3 Particle Size by Turbidimetric Methods—Like the sedi-mentation method, the turbidimetric methods provide classsizes and a percentage by weight for each class size, and thecalculation is the same as that in Table 2. However, frequentlya weight distribution curve is obtained from data not directlyconvertible into the class-size distribution table. In such cases,reconstruct the size-weight distribution table from the distri-bution by weight curve.5.4 Particle Size by Absorption and PermeabilityMethods—The absorption and permeability methods, and a fewothers, provide no means of making a distribution curve.Therefore, obtain specific surface either as square metres percubic centimetre, or as square metres per gram of material. Inthe first case, where s equals square metres per cubiccentimetre, the equation is as follows:SSD 5 6/s (3)In the second case, where S equals square metres per gram(Note), the equation is as follows:SSD 5 6/~sp gr 3 s! (4)NOTE 1—Example—Channel black has a specific gravity of 2.0. If thespecific surface in square metres per gram is reported as 94.0, then:SSD 5 6/~2 394! 5 0.032 (5)6. Calculation and Report6.1 To determine the coarseness and dispersion parametersfrom the microscopical data of Table 1, draw Curve I of Fig. 1,using the cumulative weight percentage and the upper classsize units of Table 1. From this curve, read the CP at the pointwhere the curve crosses the 99.5 % line, that is, 8.7, and obtainthe DP from the sizes where the curve crosses the 25 and 75 %lines; then calculate as follows:SSD 5 126 653.1/22 733.1 5 5.57 µm (6)p15 d75%2d25% 5 0.70 µmDP 5 100 p1/SSD 5 ~100 30.70!/5.57 5 12.6CP 5 8.7 µmTABLE 1 Example of Data Sheet for Microscopic MethodClass Limits, µmMean ClassSize, dFrequency, fd2fd3fd2f,%CumulativeWeight, %Lower Upper0.25 0.75 0.5 71.4 17.8 8.9 0.007 0.0070.75 1.25 1.0 50.9 50.9 50.9 0.040 0.0471.25 1.75 1.5 57.9 130.2 195.4 0.154 0.1911.75 2.25 2.0 36.9 147.5 295.0 0.233 0.4242.25 2.75 2.5 41.1 256.8 641.9 0.506 0.932.75 3.25 3.0 34.5 310.9 932.7 0.736 1.693.25 3.75 3.5 34.5 423.2 1 481.2 1.17 2.863.75 4.25 4.0 21.0 336.1 1 344.5 1.06 3.924.25 4.75 4.5 42.0 850.8 3 828.8 3.02 6.944.75 5.25 5.0 81.2 2 030.8 10 154.0 8.02 14.965.25 5.75 5.5 283.8 8 586.3 47 225.0 37.25 52.215.75 6.25 6.0 155.9 5 613.4 33 680.0 26.60 78.816.25 6.75 6.5 71.0 2 998.1 19 487.9 15.38 94.196.75 7.25 7.0 7.9 388.9 2 722.4 2.15 96.347.25 7.75 7.5 5.1 288.8 2 166.3 1.71 98.057.75 8.25 8.0 4.2 268.9 2 151.4 1.71 99.763.25 8.75 8.5 0.5 33.7 286.8 0.23 99.99Totals 999.8 22 733.1 126 653.1TABLE 2 Example of Data Sheet for Sedimentation MethodDiameter Class Size LimitsClass SizeDiameter,d,µmWeight %,d3fd2fCumulativeWeight, %Lower Upper0.0 0.5 0.25 11.0 44.00 11.00.5 1.0 0.75 10.0 13.33 21.01.0 1.5 1.25 10.0 8.00 31.01.5 2.0 1.75 9.0 5.14 40.02.0 3.0 2.50 15.0 6.00 55.03.0 4.0 3.50 9.5 2.71 64.54.0 5.0 4.50 8.5 1.89 73.05.0 7.5 6.25 12.5 2.00 85.57.5 10.0 8.75 8.0 0.91 93.510.0 15.0 12.50 5.3 0.42 98.815.0 20.0 17.50 1.2 0.07 100.020.0 30.0 25.00 0.0 0.00Totals 100.0 84.47D1366 − 86 (2012)26.2 To determine the coarseness and dispersion parametersfrom the sedimentation data of Table 2, draw Curve II of Fig.1, using the cumulative weight percentage and upper class sizeunits of Table 2. From this curve, determine the coarseness anddispersion parameters as described in 5.1, as follows:SSD 5(d3f/(d2f 5 100.0/84.47 5 1.183 µ m (7)DP 5 17.0 µ mp25 5.30 2 1.18 5 4.12 µmDP 5 100 p2/SSD 5 348.0CP 5 17.0 µm6.3 While theoretically the size of pigment particles isindependent of the method of determination used, it is recog-nized that various methods of determining subsieve particlesize distribution give somewhat different results, depending onthe assumption made in the particle method. It isrecommended, therefore, that the method of determinationalways be made a part of the report of the size distributiondetermined under this practice.7. Keywords7.1 microscopic; pigments; sedimentation; turbidimetricpermeability absorptionASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. 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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 service@astm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http://www.copyright.com/FIG. 1 Curves for Obtaining Coarseness and Dispersion ParametersD1366 − 86 (2012)3