1、Designation: D4708 12Standard 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
2、 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.
3、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 pare
4、ntheses 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 limitati
5、ons 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 Tr
6、ansmission 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 appl
7、iedfilms 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 Metho
8、ds 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 Micro
9、meter 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 P
10、lates, coated with halosilane compound.5.3.4 Steel Panelwrapped with Tedlar6polyvinyl fluoridefilm, preferably 25 to 50m 9 (1 to 2 mils) thick.NOTE 1Other substrates that may be suitable are 250-m (10-mil)thick polyethylene, polypropylene sheet, photographic paper, polishedsteel, and fluoropolymer c
11、oated 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 Propert
12、ies 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 servi
13、ceastm.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.,
14、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 r
15、elease paper, Form RP-1K, size858 by 1114 in., 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
16、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 States16. Procedure6.1 Prepare the free fil
17、ms by one of the following proce-dures:NOTE 2To 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 (12 in.) of waste betw
18、eenspecimens.6.1.1 FEP Substrate:6.1.1.1 Apply each material to be tested to a sheet of FEPthat has been treated as follows: First, cover a smooth, flatpolished glass plate with a sheet of FEP. Coat the sheetuniformly with a light coat of a dry fluorocarbon lubricant andallow to dry for 24 h at stan
19、dard conditions. Then apply auniform wet coating of the test material on the sheet by one ofthe procedures given in Practices D823.6.1.1.2 Dry the applied films in 23 6 2C (73.5 6 3.5F)and 50 6 5 % humidity, or bake under conditions mutuallyagreeable to the producer and the user. Dry film thicknesse
20、smust not vary by more than the specified or agreed upontolerances of the average film thickness and must be free ofvisible flaws. Most films with a thickness of less than 50 m(2.0 mil) are very difficult to handle.6.1.1.3 When required for further treatment such asweathering, remount the coated she
21、et on a convenient smooth,flat substrate such as a glass or steel panel.6.1.1.4 Age or expose the coated sheet to conditions mutu-ally agreed upon. At the end of the aging or exposure period,remove the sheet-backed film from the glass or metal substrateand cut the specimens to size using a sharp kni
22、fe or theprecision cutter (Note 2). Carefully strip the coating film fromthe sheet substrate.6.1.2 Silicone Coated Paper:6.1.2.1 Apply each material to a sheet of silicone coatedpaper. First, cover a smooth, flat substrate with a sheet of asilicone-coated release paper. Then apply a film of the mate
23、rialunder test, dry or cure, expose or treat if required, and preparetest specimens as described in 6.1.1.6.1.3 Halosilane Coated Glass PlatesApply each materialto a glass plate coated with a halosilane compound. First, coata glass plate with a thin film of a halosilane compound and dry.Then apply a
24、 film of the material under test, dry or cure, exposeor treat if required, and prepare test specimens as described in6.1.1.6.1.4 Tedlar Wrapped Steel Panel (for specimens that are tobe baked).6.1.4.1 Apply each material that is to be tested to the Tedlarsurface. First, wrap the panel with the Tedlar
25、 film, tape the filmin place and bake the combination at 165C (330F) for 15 minto shrink the film onto the panel. Allow the panel to cool andwipe the surface with i-propanol. Then apply the materialunder test, bake as required, then expose or treat if required,and prepare test specimens as described
26、 in 6.1.1.7. Keywords7.1 film; halosilane coated glass plates; lacquer; organiccoatings; paints and related coatings; polyhexafluoropylene(FEP) substrate; silicone-coated paper; substrates; surfacepreparation; tension (tensile) properties/tests; vapors; varnishesSUMMARY OF CHANGESCommittee D01 has i
27、dentified the location of selected changes to this standard since the last issue (D4708 07) that may impact the use of this standard. (Approved July 1, 2012.)(1) Listing or an additional Test Methods (E96/E96M) wherethis method for preparing test films may be useful (Sections 2and 4).(2) Additional
28、suitable substrates have been added, steel panelstightly wrapped with Tedlar polyvinyl fluoride film (Section5.3.4) and polypropylene sheet (Note 1 under Section 5).(3) The procedure for preparing Tedlar wrapped steel panels isgiven in Section 6.1.4.1.ASTM International takes no position respecting
29、the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard
30、 is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International
31、Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This
32、 standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D4708 122
