1、Designation:D470819Standard 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 numbe
2、r 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.1.2 The val
3、ues 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 safet
4、y,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.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 Int
5、ernational Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D823 Practices for Producing Films of Uniform Thicknessof Paint,Coatings and Related Products on Test PanelsD1005 Test Method for
6、 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-ingsD5590 Test Method for Determining the Resistance of PaintFilms and Related Coatings to Fungal
7、 Defacement byAccelerated Four-Week Agar Plate AssayE96/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 appropriat
8、e 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),moisture vapor permeability(Test Methods
9、D1653 and E96/E96M),microbiological activ-ity resistance(Test Method D5590),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 Micr
10、ometer Film Thickness Gage,as described in TestMethod D1005.5.3 Release Substrates,any film releasing flat substratewhich does not alter film properties and which allows thecasting of coating films with a uniform thickness.Examples ofsuitable substrates are as follows:5.3.1 Sheet of FEP(polyhexafluo
11、ropropylene).5.3.2 Sheet of Silicone Coated Paper,preferably 125-m(5-mil)thick.5.3.3 Glass Plates,coated with halosilane compound.5.3.4 Steel PanelWrapped with polyvinyl fluoride film,preferably 25 to 50m(1 to 2 mils)thick.5.3.5 Flat PanelCoated with release agent.5.3.6 Polytetrafluoroethylene Sheet
12、(with or without glassfiber reinforcement)wiped with diluted surfactant solution asneeded.5.3.7 Polyethylene Film preferably 50 m in thickness,wrapped around a glass sheet.5.4 Surfactant SolutionDiluted surfactant solution.Fluo-rinated surfactants are preferred due to their high efficiency.NOTE1Solu
13、tion comprising 0.5 to 1%fluorinated surfactant inisopropyl alcohol was found to be suitable for some coatings.Check thatthe use of surfactant does not alter the coating film properties to be tested.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings,Materials
14、,and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Current edition approved March 1,2019.Published August 2019.Originallyapproved in 1987.Last previous edition approved in 2012 as D4708 12.DOI:10.1520/D4708-19.2For referenced ASTM s
15、tandards,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.*A Summary of Changes section appears at the end of this standardCopyright ASTM Internat
16、ional,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.1 5.5 Release Agent,film forming release agents,for examplefluoropolymers,silicones,polyvinyl alcohol
