ASTM_D_2370_-_16.pdf

Designation:D237016Standard Test Method forTensile Properties of Organic Coatings1This standard is issued under the fixed designation D2370;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the determination of theelongation,tensile strength,and stiffness(modulus of elastic-ity)of organic coatings when tested as free films.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and 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:2D823 Practices for Producing Films of Uniform Thicknessof Paint,Varnish,and Related Products on Test PanelsD882 Test Method for Tensile Properties of Thin PlasticSheetingD1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD3980 Practice for Interlaboratory Testing of Paint andRelated Materials(Withdrawn 1998)3D4708 Practice for Preparation of Uniform Free Films ofOrganic Coatings3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 elongation at break,nthe increase in specimenlength from the point of initial load application to the point offilm rupture in a tension test.3.1.2 gage length,nthe initial length of the test specimenbetween the jaws of the tensile tester.3.1.3 stiffness(modulus of elasticity),nthe load per unitarea required to elongate the film 1%from the first point in thestress-strain curve where the slope becomes constant.3.1.4 stress-strain curve,nthe curve resulting from a plotof tensile load against the distance of jaw separation(elonga-tion of specimen).3.1.5 tensile strength(nominal),nthe load per originalunit area at which a specimen fails or yields in a tension(pull)test.4.Summary of Test Method4.1 Free unsupported films of the materials to be tested areprepared in accordance with Test Method D4708.The tensileproperties of the free films are determined by means of a tensiletesting apparatus.5.Significance and Use5.1 Tensile properties determined by this method are ofvalue in studying the behavior of coatings subjected to envi-ronmental stresses,such as those produced by aging andweathering.(See Refs.(1-10).)45.2 Tensile properties may vary with specimen thickness,method of preparation,gage length,rate of load application,tensile tester response,and type of grips used.Consequently,where precise comparative results are desired,these factorsmust be carefully controlled.6.Apparatus6.1 Equipment for applying films of uniform thickness asdescribed in Practices D823.6.2 Micrometer Film Thickness Gage as described in TestMethod D1005.1This 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 July 1,2016.Published November 2016.Originallyapproved in 1965.Last previous edition approved in 2010 as D2370 98(2010).DOI:10.1520/D2370-16.2For 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.4Boldface numbers in parentheses refer to the list of references at the end of thisstandard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.3 Tensile Tester of the constant rate of jaw separation type,equipped with load cells having capacities of 1 to 50 N(0.2 to10 lb),and equipped with computer with tester controllingsoftware,or optionally an indicating device such as an elec-tronic constant speed chart recorder,a digital device thatdisplays numerical values,or a printer that records the numeri-cal values.Tensile tester can also be equipped with a video-extensometer and environmental chamber,when higher accu-racy of test is required and testing is conducted at an elevatedor low temperature.6.4 Precision Specimen Cutter having a double blade with afoot to hold the sample in place5or other suitable sharp cutterblade.7.Test Specimens7.1 The test specimens shall be free films having a widththat is between 13 and 25 mm(12and 1 in.).No specimen shallvar