1、Designation: D7540 09 (Reapproved 2013)Standard Practice forDispersion of Chromatic Pigments with a MechanicalMuller1This standard is issued under the fixed designation D7540; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r 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.1. Scope1.1 This practice is intended to be used to disperse achromatic pigment for subsequent testing.1.2 This practice does
3、 not apply to white pigments.NOTE 1The dispersion portion of Test Method D3022 is similar to thispractice, but it utilizes a miniature sandmill rather than a mechanicalmuller, to disperse the chromatic pigment.NOTE 2The dispersion portions of Test Methods D332 and D2745 aresimilar to this practice,
4、but they are intended for use with white pigments,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 wi
5、th 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. Specific hazardstatements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2D332 Test Method
6、 for Relative Tinting Strength of WhitePigments by Visual ObservationD2745 Test Method for Relative Tinting Strength of WhitePigments by Reflectance MeasurementsD3022 Test Method for Color and Strength of Color Pig-ments by Use of a Miniature SandmillE284 Terminology of Appearance3. Terminology3.1 D
7、efinitionsDefinitions of appearance terms used inthis practice may be found in Terminology E284.4. 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 co
8、mpared for 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 mulle
9、r is a quick 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. A
10、nycolor 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 b
11、e added 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 sur
12、faces of 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 spatul
13、a having a 75 to 150-mm (3 to6-in.) blade.7. Materials7.1 Reference StandardA standard pigment of the sametype and grade as the pigment to be tested, as agreed uponbetween the purchaser and the seller.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materi
14、als, and Applications and is the direct responsibility ofSubcommittee D01.24 on Physical Properties of Liquid Paints and Paint Materials.Current edition approved June 1, 2013. Published June 2013. Originallyapproved in 2009. Last previous edition approved in 2009 as D7540 09. DOI:10.1520/D7540-09R13
15、.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 ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box
16、C700, West Conshohocken, PA 19428-2959. United States17.2 VehicleA solvent-free vehicle, such as a No. 1 ligtho-graphic varnish, with 0.8 % each of cobalt and manganesedriers (6 % types).8. Hazards8.1 Some pigments are potentially toxic and thereforeshould be handled with care. Obtain specific preca
17、utions fromthe manufacturer or supplier.8.2 Many solvents and paint vehicles present explosion, fire,and toxicity hazards, so they should accordingly be handledwith care. Again, obtain specific precautions from the manu-facturer or supplier.9. Dispersing Conditions9.1 The conditions for dispersing t
18、he pigment on the me-chanical muller should be such that the maximum tintingstrength is developed. For each pigment and each dispersingvehicle the development of tinting strength by the mechanicalmuller is influenced by the force applied, the number ofrevolutions, the mass of the pigment, and the ma
19、ss of thevehicle. The conditions for obtaining the maximum tintingstrength with the mechanical muller can be determined byfollowing the procedure in Appendix X1.9.2 If these conditions are known for a particular pigmentwith a particular vehicle, or if the purchaser and seller agreeupon a particular
20、set of conditions, there is no need to carry outthe procedure in Appendix X1.10. Dispersion Procedure10.1 Decide, by agreement or by experimentation, as dis-cussed in Section 9, the following dispersing conditions:10.1.1 Force applied to the muller plates;10.1.2 Number of revolutions;10.1.3 Mass of
21、the pigment, 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 th
22、e spatula 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 th
23、e mulling 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 pa
24、ste and 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 te
25、sts for 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; dispersions; mullersFIG. 1 A Muller-Type Labor
26、atory Grinder/Disperser (Courtesy ofPaul N. Gardner Company, Inc.)D7540 09 (2013)2APPENDIX(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 t
27、he mechanical muller.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 am
28、ounts and mixthem 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 th
29、e finger. Weigh 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 volu
30、me of that pasteprepared 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 t
31、he muller plates 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 descri
32、bed in X1.1.3, 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 thetintin
33、g strength is still 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 re
34、quired formaximum 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
35、 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 any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject
36、to revision at 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
37、. Your comments 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
38、 copyrighted by ASTM International, 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 serviceas
39、tm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).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 50) 100 (2 50) 200 (4 50) 100 (2 50)Mas of color pigment, g 0.75 1.0 0.6 2.0Mass of dispersing vehicle, g 1.8 1.7 1.4 1.0D7540 09 (2013)3
