ASTM_D_4958_-_10_2016.pdf

Designation:D495810(Reapproved 2016)Standard Test Method forComparison of the Brush Drag of Latex Paints1This standard is issued under the fixed designation D4958;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 test method is a standardized brushout procedurefor comparing the brush drag of architectural type solvent-borne paints.1.2 With slight modifications this test method is also appli-cable to solvent-borne paints.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.2.Referenced Documents2.1 ASTM Standards:2D1475 Test Method For Density of Liquid Coatings,Inks,and Related ProductsD3924 Specification for Environment for Conditioning andTesting Paint,Varnish,Lacquer,and Related MaterialsD3925 Practice for Sampling Liquid Paints and RelatedPigmented CoatingsD4287 Test Method for High-Shear Viscosity Using a Cone/Plate ViscometerD5068 Practice for Preparation of Paint Brushes for Evalu-ation3.Terminology3.1 Definitions:See Paint/Coatings Dictionary3for defini-tion of terms used in this test method.3.1.1 brush-dragresistance encountered when applying acoating by brush.4.Summary of Test Method4.1 A50-mm(2-in.)polyester brush is used to apply the testpaint on a 1000-cm2(1.076-ft2)test area.The application ismade at a spreading rate of 9.82 m2/L(400 ft2/gal)and iscompleted in 30 to 35 s.The degree of brush drag is ratedsubjectively using a series of standard descriptive termscorresponding to numerical values of 1 to 10.The rank order ofa set of samples is thereby established.5.Significance and Use5.1 As the brush drag of a paint increases,any naturaltendency on the part of the painter to overspread the paint isreduced.When all other factors are held constant,increasedbrush drag will result in greater film thickness with consequentimprovement in durability and hiding.Conversely,sometimesit might be preferred to have a lesser degree of brush drag foreasier application(that is,the amount of time and effort inapplying a paint to a specific area is reduced with a lesserdegree of brush drag).5.2 This test method provides a standardized brushoutprocedure for the evaluation of brush drag as an alternative tocustomary informal ad hoc procedures.Its objective is tomaximize the reliability and precision with which this charac-teristic may be determined.NOTE1The brush drag of paints is directly related to their high-shearviscosity.There is generally good rank order agreement between resultsobtained by this method and Test Method D4287.The sensitivity of thisbrushout method has been found sufficient to distinguish between brush-abilities corresponding to high-shear viscosity differences not lower than0.3 poise(0.03 Pa.s).Round robin data show that rank order agreementbetween the brushout and viscometric methods is poor when latex andsolvent-borne paints are part of the same comparison group.This is theresult of these two paint types having markedly different rheologicalproperties that affect the relative perception of brush drag.46.Apparatus6.1 Brush,50-mm(2-in.)polyester filament,70-mm(234-in.)length-out,14 mm(916in.)thick,with a chiseled tip.1This 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 April 1,2016.Published April 2016.Originallyapproved in 1989.Last previous edition approved in 2010 as D4958 10.DOI:10.1520/D4958-10R16.2For 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.3Available from Federation of Societies for Coatings Technology(FSCT),492Norristown Rd.,Blue Bell,PA 194222350,http:/www.coatingstech.org.4Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D01-1072.ContactASTM CustomerService at serviceastm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 NOTE2All tests of a given series of paints,within or betweenlaboratories,should be carried out with commercially identical brushes.6.2 Stopwatch.6.3 Balance,capable of weighing accurately to 0.1 g.6.4 Test charts,with a sealed surface,having 1000 cm2(1.076 ft2)of test area.57.Samp