ASTM_D_5178_-_13.pdf

Designation:D517813Standard Test Method forMar Resistance of Organic Coatings1This standard is issued under the fixed designation D5178;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 covers the determination of the marresistance on smooth,flat surfaces.Results are expressed interms of force-to-mar films of organic coatings such as paint,varnish,and lacquer when applied to smooth,flat planar panelsurfaces.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 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:2D609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint,Varnish,Conversion Coatings,andRelated Coating ProductsD823 Practices for Producing Films of Uniform Thicknessof Paint,Varnish,and Related Products on Test PanelsD1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD1186 Test Methods for Nondestructive Measurement ofDry Film Thickness of Nonmagnetic Coatings Applied toa Ferrous Base(Withdrawn 2006)3D1400 Test Method for Nondestructive Measurement of DryFilm Thickness of Nonconductive Coatings Applied to aNonferrous Metal Base(Withdrawn 2006)3D2691 Method for Microscopical Measurement of Dry FilmThickness of Coatings on Wood Products(Withdrawn1992)33.Terminology3.1 Definitions:3.1.1 mar resistance,nthe ability of a coating to resistdamage caused by light abrasion.As just defined,it is aresistance of the surface of the coating to permanentdeformation,resulting from the application of a dynamicmechanical force.4.Summary of Test Method4.1 The materials under test are applied at uniform thicknessto flat panels of uniform surface texture.After drying/curing,the mar resistance is determined by pushing the panels beneatha rounded stylus or loop that is loaded in increasing amountsuntil the coating is marred.5.Significance and Use5.1 In some situations,marring of coatings applied tosubstrates under typical use conditions is unacceptable.Thistest method has been found useful in differentiating the degreeof marring of coatings on substrates.It is most useful inproviding relative ratings for a series of coated panels exhib-iting significant differences in marring.5.2 In a limited laboratory study,meaningful mar resultswere impossible when powder coatings were tested.The marmarking,that is,scratches,became less perceptible with time.Therefore,powder coatings may not be applicable coatings forthis test method.6.Apparatus6.1 Application Equipment,as described in Practices D823.6.2 Film-Thickness Measuring Apparatus,as described inTest Methods D1005,D1186,D1400,or D2691.6.3 Balanced Beam Scrape Adhesion and Mar Tester(Fig.1and Fig.2),consisting of a balanced beam to which is secureda platform for supporting weights,and a rod at an angle of 45that holds the scraping loop.The rod shall be set so that thescraping loop contacts test surfaces directly below the weights.The loop shall be116-in.(1.6 mm)diameter rod,bent into a“U”shape with an outside radius of 0.128 6 0.002 in.(3.25 61This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Current edition approved May 15,2013.Published May 2013.Originallyapproved in 1991.Last previous edition approved in 2008 D5178 98(2008).DOI:10.1520/D5178-13.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 0.05 mm)and hardened to Rockwell HRC 56 to 58,and shallbe a smooth finish.The loop can be either chromium plated,nickel plated,or heat treated polished steel as agreed uponbetween the purchaser and the supplier.These testers areadjustable to accommodate flat,metallic,and nonmetallicspecimens to 0.5-in.(12-mm)thick and 4 to 16 in.(100 to 400mm)wide and long;the specimen should be at least12-in.(12-mm)wide.7.Preparation of Specimens7.1 Apply the materials under test to panels of the compo-sition and