ASTM_D_7540_-_09_2013.pdf

Designation:D754009(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 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.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 white pigments.NOTE1The 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.NOTE2The dispersion portions of Test Methods D332 and D2745 aresimilar to this practice,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 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.Specific hazardstatements are given in Section 8.2.Referenced Documents2.1 ASTM Standards:2D332 Test Method 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 DefinitionsDefinitions 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 compared 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 muller 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.Anycolor 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 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 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 spatula 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,Materials,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/D7540-09R13.2For 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 C700,West Conshohocken,PA 19428-2959.United States1 7.2 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 precautions 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 condi