1、Designation: D 7540 09Standard Practice forDispersion of Chromatic Pigments with a MechanicalMuller1This standard is issued under the fixed designation D 7540; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. 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 practice is intended to be used to disperse achromatic pigment for subsequent testing.1.2 This practice does not apply to wh
3、ite pigments.NOTE 1The dispersion portion of Test Method D 3022 is similar tothis practice, but it utilizes a miniature sandmill rather than a mechanicalmuller, to disperse the chromatic pigment.NOTE 2The dispersion portions of Test Methods D 332 and D 2745are similar to this practice, but they are
4、intended for use with whitepigments, rather than chromatic pigments.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. I
5、t 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. Specific hazardstatements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2D 332 Test Method for Relativ
6、e Tinting Strength of WhitePigments by Visual ObservationD 2745 Test Method for Relative Tinting Strength of WhitePigments by Reflectance MeasurementsD 3022 Test Method for Color and Strength of ColorPigments by Use of a Miniature SandmillE 284 Terminology of Appearance3. Terminology3.1 Definitions:
7、 Definitions of appearance terms used in thispractice may be found in Terminology E 284.4. Summary of Practice4.1 Pigments are dispersed in a suitable vehicle with amechanical muller. Test and standard pigments are treatedidentically. Opaque drawdowns may be made from the disper-sions and compared f
8、or color and strength differences eithervisually or instrumentally.5. Significance and Use5.1 The results obtained with a mechanical muller do notnecessarily correlate directly with an industrial situation wheredifferent dispersing conditions exist. However, dispersion witha mechanical muller is a q
9、uick and inexpensive way to preparespecimens for testing the color and strength of a pigment forroutine quality control.5.2 By following the procedure described in Appendix X1,the conditions for achieving the maximum practical degree ofdispersion with a mechanical muller may be determined. Anycolor
10、and strength tests done with the dispersions should becarried out under these conditions.6. Apparatus6.1 Balances(1) A balance sensitive to 10 mg and (2) ananalytical balance sensitive to 1.0 mg.6.2 Muller, Mechanical, equipped with ground-glass platesto which a variable but known force may be added
11、 in 220-N(50-lbf) increments. The driven glass plate shall have a speedof rotation of between 70 and 120 r/min and the apparatus shallhave an arrangement for pre-setting the number of revolutionsin multiples of 50. See Fig. 1 for an example of such a device.6.3 Rubbing SurfacesThe rubbing surfaces o
12、f the groundglass plates shall be kept sharp by removing them from themuller and grinding them face-to-face with No. 303 opticalemery, or its equivalent, and water.6.4 Small Glass Slab or other nonabsorbent material, suit-able for weighing and mixing pigment pastes.6.5 SpatulaAflexible spatula havin
13、g a 75 to 150-mm (3 to6-in.) blade.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.24 on Physical Properties of Liquid Paints 10.1.2 Number of revolutions;10.1.3 Mass of the p
14、igment, and10.1.4 Mass of the vehicle.10.2 Applying these decisions, prepare a dispersion of thereference standard pigment. Weigh onto a glass slab to within2 mg, the appropriate quantities of the standard pigment andthe dispersing vehicle. Mix the pigment and vehicle togetherthoroughly with the spa
15、tula and transfer the mixture to thelower plate of the muller. Spread the mixture in a pathapproximately 100 mm wide and halfway between the centerand rim of the lower plate, and clean the spatula as much aspossible by wiping it on the upper plate of the muller. Close theplates and carry out the mul
16、ling stages of 50 revolutions; aftereach stage collect the paste from both plates with the spatulaand spread it around the 100-mm path on the lower plate,wiping the spatula on the upper plate as before. When themulling has been carried out for the prescribed number ofrevolutions, collect the paste a
17、nd store it. Clean the glass slab,the muller plates, and the spatula, and repeat the procedurewith exactly the same quantities of the test sample and vehicle.Collect the paste from this sample and store it. Clean the glassslab, the muller plates, and the spatula. The two pastes may beused in tests f
18、or color and strength.NOTE 3The most common sources of error in this procedure areinaccurate weighing, incomplete transfer of the pigment and vehiclemixture, and contamination of the plates by previous specimens.11. Keywords11.1 chromatic pigments; dispersion; mullerFIG. 1 A Muller-Type Laboratory G
19、rinder/Disperser (Courtesy ofPaul N. Gardner Company, Inc.)D7540092APPENDIX(Nonmandatory Information)X1. DISPERSING CONDITIONS FOR MAXIMUM TINTING STRENGTHX1.1 The following describes a test method for determiningthe conditions for achieving the maximum level of tintingstrength with the mechanical m
20、uller.X1.1.1 Determine the appropriate ratio of color pigment todispersing vehicle by performing the following operations:Tare off the weight of a glass slab on a balance. Weigh 1.00 60.01 g of the standard pigment on to the glass slab. Adddispersing vehicle to the pigment in small amounts and mixth
21、em together with the spatula. Keep adding the vehicle andmixing the paste until the pigment is completely wetted and aworkable paste is obtained. At this point the consistency of thepaste should be such that a dab of the paste will drop from thespatula when it is gently tapped with the finger. Weigh
22、 thepaste, and subtract the mass of the pigment to determine themass of the vehicle. Calculate the pigment to vehicle massratio. Repeat the operations described above for the testpigment.X1.1.2 Determine the appropriate amount of pigment to useby estimating, to within 0.2 mL, the volume of that past
23、eprepared in X1.1.1 that has the smallest pigment-to-vehiclemass ratio. Calculate the masses of pigment and vehicle neededto give a paste having a volume of about 2.0 mL. Round theamount of pigment down and the amount of vehicle up to thenearest 0.1 g.X1.1.3 Apply 440 N (100 lbf) to the muller plate
24、s andprepare a tint of the standard pigment. Use the amounts of thecolor pigment and dispersing vehicle determined in X1.1.2 andmull the paste for 100 revolutions in two stages of 50revolutions each.X1.1.4 Prepare three more specimens from the same samplefollowing the procedure described in X1.1.3,
25、but mull thesespecimens, in stages of 50 revolutions, for 200, 300, and 400revolutions, respectively.X1.1.5 Compare each of the four specimens, one to theother, for tinting strength and determine the minimum numberof revolutions necessary to achieve full tinting strength. If thetinting strength is s
26、till developing after 400 revolutions, repeatX1.1.3-X1.1.5 with 220 N (50 lbf) more force on the mechani-cal muller plates.X1.1.6 Record the appropriate amounts of pigment andvehicle (by X1.1.2), the force applied to the mechanical mullerplates and the minimum number of revolutions required formaxim
27、um tinting strength.X1.1.7 Table X1.1 lists, as examples, the dispersing condi-tions used in one interlaboratory study. The vehicle used wasNo. 1 lithographic varnish with 0.8 % each of cobalt andmanganese driers (6 % types).ASTM International takes no position respecting the validity of any patent
28、rights asserted 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
29、any time by the 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
30、 will receive careful 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
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32、; or through the ASTM website(www.astm.org).TABLE X1.1 Dispersing Conditions Used in an Interlaboratory StudyPigment Type Pthalocyanine Green Yellow Iron Oxide BON Red Molybdate OrangeForce applied to the muller plates, N (lb) 440 (100) 440 (100) 440 (100) 440 (100)Total number of revolutions 400 (8 3 50) 100 (2 3 50) 200 (4 3 50) 100 (2 3 50)Mas of color pigment, g 0.75 1.0 0.6 2.0Mass of dispersing vehicle, g 1.8 1.7 1.4 1.0D7540093
