ASTM_D_4708_-_12.pdf

Designation:D470812Standard Practice forPreparation of Uniform Free Films of Organic Coatings1This standard is issued under the fixed designation D4708;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.Scope*1.1 This practice covers the preparation of free films oforganic coatings for use in determining the physical propertiesof the coatings.Procedures are given for preparing free filmson three alternative substrates.These substrates are treated FEP(fluorinated ethylene-propylene)sheet,silicone coated paper,and halosilane coated glass plates.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D823 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 MicrometersD1653 Test Methods for Water Vapor Transmission of Or-ganic Coating FilmsD2370 Test Method for Tensile Properties of Organic Coat-ingsE96/E96M Test Methods for Water Vapor Transmission ofMaterials3.Summary of Test Method3.1 Free films are prepared by depositing a uniform wetcoating of the test material on a release substrate.The appliedfilms are dried or baked,cut into appropriate size for theintended physical property test,and then stripped from therelease substrate.4.Significance and Use4.1 Free films are required for conducting tests to evaluatephysical and mechanical properties such as tensile and elon-gation(Test Methods D2370 and E96/E96M),moisture vaporpermeability(Test Methods D1653),and other physical prop-erties of organic coatings where the substrate may interferewith the determination.5.Apparatus and Materials5.1 Equipment,for applying films of uniform thickness asdescribed in Practices D823.5.2 Micrometer Film Thickness Gage,as described in TestMethod D1005.5.3 Alternative Release Substrates:5.3.1 Sheet of FEP(polyhexafluoropropylene),preferably50-m(2-mils)thick,coated with a thin film of a drylubricant.3,45.3.2 Sheet of Silicone Coated Paper,preferably 125-m(5-mil)thick.5,45.3.3 Glass Plates,coated with halosilane compound.5.3.4 Steel Panelwrapped with Tedlar6polyvinyl fluoridefilm,preferably 25 to 50m 9(1 to 2 mils)thick.NOTE1Other substrates that may be suitable are 250-m(10-mil)thick polyethylene,polypropylene sheet,photographic paper,polishedsteel,and fluoropolymer coated metal panels.5.4 Precision Specimen Cutter,having a double blade with afoot to hold the sample.7,41This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Current edition approved July 1,2012.Published August 2012.Originallyapproved in 1987.Last previous edition approved in 2007 as D4708 07.DOI:10.1520/D4708-12.2For 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 sole source of supply of dry lubricant(MS-122 Fluorocarbon ReleaseAgent)known to the committee at this time is Miller-Stephenson Chemical Co.,Inc.,55 Backus Ave.,Danbury,CT 06810.4If you are aware of alternative suppliers,please provide this information toASTM International Headquarters.Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.5The sole source of supply of silicone coated release paper,Form RP-1K,size858by 1114in.,known to the committee at this time is the Leneta Co.,15 WhitneyRd.,Mahwah,NJ 07430.6Tedlar is a registered trademark of E.I.du Pont de Nemours and Company.7The sole source of supply of the JDC Precision Sample Cutter known to thecommittee at this time is the Thwing-Albert Instrument Co.,14 West Collins Ave.,West Berlin,NJ 08091.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.Procedure6.1 Prepare the free films by one of the following proce-dures:NOTE2To prepare specimens for tensile property tests a precisionspecimen cutter must be used to ensure nick-free edges on the specimens.Even with this instrument,it is necessary to cut each specimenindependently,allowing at least 13 mm(12in.)of wa