ASTM_D_2486_-_06_2012e1.pdf

Designation:D248606(Reapproved 2012)1Standard Test Methods forScrub Resistance of Wall Paints1This standard is issued under the fixed designation D2486;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.1NOTEFootnotes in 6.3.1 were editorially updated in February 2012.1.Scope1.1 These test methods cover a procedure for determiningthe resistance of wall paints to erosion caused by scrubbing,referred to herein after as“scrub resistance.”1.2 Two test methods are covered as follows:1.2.1 Test Method ACycles-to-failure obtained on testpaint.1.2.2 Test Method BRatio expressed as a percentage ofcycles-to-failure obtained on the test paint to that obtained ona concurrent run with a known reference paint.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:2D3924 Specification for Environment for Conditioning andTesting Paint,Varnish,Lacquer,and Related MaterialsD4213 Test Method for Scrub Resistance of Paints byAbrasion Weight Loss3.Summary of Test Method3.1 In Test Method A,the test paint is applied to a blackplastic panel.After curing,the coated panel is placed over a12.7 wide by 0.25-mm thick(12-in.by 10-mil)shim and heldin place on a drawdown plate in a washability machine bymeans of a gasketed frame.The coated panel is then scrubbedwith a bristle brush and an abrasive scrub medium until thepaint film is removed in one continuous thin line across theshim.3.2 In Test Method B,the test paint and a reference paint areapplied simultaneously perpendicular to the length of the blackplastic panel.After curing,the coated panel is placed over two12.7 by 0.25-mm(12-in.by 10-ml)shims that are positionedunder each coating.The coatings are then scrubbed with abristle brush and an abrasive scrub medium until each paintfilm is removed in one continuous thin line across its ownshim.4.Significance and Use4.1 Paints often become soiled,especially near doorways,windows,and in work and play areas.These test methods coverthe determination of the relative resistance of different paints toerosion when repeatedly scrubbed during the life of the paint.4.2 Test Method D4213 is a similar scrub resistance testusing a weight-loss technique and reporting volumetric filmerosion rates.4.3 Test Method A measures scrub resistance by the tradi-tional cycles-to-failure concept.Poor correlation in scrubtesting can be attributable to among other things variations inthe stiffness of the brush bristles,condition of washabilitytester,application and drying conditions.In an attempt toimprove reproducibility,Test Method B has been developed.5.Apparatus5.1 Straight Line Washability Machine.5.1.1 Accessory Apparatus:(see Figs.1 and 2).5.1.1.1 Nylon Bristle Brush and Accessories,(total weight454 6 10 g).5.1.1.2 Drawdown Plate,454 by 165 by 6.3 mm(1778by612by14in.).5.1.1.3 Brass Shims,12.7-by 0.25-mm(12-in.by 10-mils).Its length can be fitted to the width of the drawdown plate.5.2 Film Applicator,having 0.18-mm(7-mil)clearance and6.25-mm(14-in.)edge and width of 135 mm(514-in.).1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings,Materials,and Applications and are the directresponsibility of Subcommittee D01.42 on Architectural Coatings.Current edition approved Feb.1,2012.Published February 2012.Originallyapproved in 1966.Last previous edition approved in 2006 as D2486 06.DOI:10.1520/D2486-06R12E01.2For 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 6.Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.6.2 Black Plastic Panels.3,46.3 Abrasive Scrub Medium.4,56.3.1 Laboratory standardized abrasive scrub medium con-sisting of the following:gramsWater,distilled or deionized49.4AHydroxyethyl cellulose4,60.8Ammonium hydroxide,28%0.1Detergent4,72.0Trisodium phosphate,anhydrous2.0Silica4,845.0Acetic acid(glacial)0.7BPreservative4,90.03gAAdjust to achieve viscosity of 110 to 120 Krebs units before use.BVary to achieve a pH of 9.5 to 10.6.4 Reference paint when using Test Method B.3Dull