ASTM_D_4752_-_20.pdf

Designation:D475220Standard Practice forMeasuring MEK Resistance of Ethyl Silicate(Inorganic)Zinc-Rich Primers by Solvent Rub1This standard is issued under the fixed designation D4752;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 describes a solvent rub technique forassessing the MEK resistance of ethyl silicate(inorganic)zinc-rich primers.The MEK resistance of some two-component ethyl silicate zinc-rich primers has been shown tocorrelate well with the cure of the primer as determined bydiffuse reflectance infrared spectroscopy.2The technique canbe used in the laboratory,field,or in the fabricating shop.Practice D5402 is the preferred method for organic coatings.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.Specific hazard statements are given in Section 6.Consultsuppliers Safety Data Sheet(s)for specific hazard informationrelating to the solvent used.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:3D740 Specification for Methyl Ethyl KetoneD4138 Practices for Measurement of Dry Film Thickness ofProtective Coating Systems by Destructive,Cross-Sectioning MeansD5402 Practice for Assessing the Solvent Resistance ofOrganic Coatings Using Solvent RubsD7091 Practice for Nondestructive Measurement of DryFilm Thickness of Nonmagnetic Coatings Applied toFerrous Metals and Nonmagnetic,Nonconductive Coat-ings Applied to Non-Ferrous Metals3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 double rub,nthe act of rubbing a solvent saturatedcloth in one complete forward and backward motion over acoated surface.4.Significance and Use4.1 Ethyl silicate zinc-rich primers cure by the reaction ofthe vehicle with moisture,thereby providing a binder for thezinc.As relative humidity and temperature vary,so does therate of cure.A certain minimum degree of cure is necessaryprior to topcoating.It has been shown that the degree of cureof ethyl silicate zinc-rich primers can be measured by thechemical changes occurring using diffuse reflectance infraredspectroscopy.2This solvent rub test has been shown to corre-late well with the infrared spectroscopic results of sometwo-component ethyl silicate inorganic zinc systems.4.2 The degree of cure rating(Resistance Rating in Table 1)required prior to the application of specific topcoats must beagreed upon before the practice is used.5.Reagents and Materials5.1 Methyl Ethyl Ketone(MEK),in accordance with Speci-fication D740.5.2 100%Cotton,Shop Cloth,approximately 300 by 300mm(12 by 12 in.)contrasting in color to the primer to beevaluated.5.3 Squeeze Bottle.5.4 Proper Safety Equipment,as determined from the sol-vent SDS,for example,solvent resistant gloves,respirator.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.46 on Industrial Protective Coatings.Current edition approved Feb.1,2020.Published February 2020.Originallyapproved in 1987.Last previous edition approved in 2015 as D4752 10(2015).DOI:10.1520/D4752-20.2Starr,T.L.,Henton,L.E.,Lewis,W.S.,and Rideout,F.A.,“Improved FieldReliability of High Performance Coating Systems:Phase IIDevelop Proceduresand Criteria in Critical Performance Areas,”available from SSPC:The Society forProtective Coatings,800 Trumbull Drive,Pittsburgh,PA 15205,www.sspc.org.3For 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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.6.Procedure6.1 Select areas on the primer surface at least 150 mm(6 in.)l