1、Designation: D2370 98 (Reapproved 2010)D2370 16Standard 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 la
2、st 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 determ
3、ination of the elongation, tensile strength, and stiffness (modulus of elasticity) of organiccoatings when tested as free films.1.2 The values stated in inch-poundSI units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SIinch-pound units that are provi
4、ded for information only and are not considered standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicabilit
5、y of regulatorylimitations prior to use.Specific hazard statements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2D823 Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on Test PanelsD882 Test Method for Tensile Properties of Thin Plastic S
6、heetingD1005 Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using MicrometersD3980 Practice for Interlaboratory Testing of Paint and Related Materials (Withdrawn 1998)3D4708 Practice for Preparation of Uniform Free Films of Organic Coatings3. Terminology3.1 Definitions of Term
7、s Specific to This Standard:3.1.1 elongation, elongation at break, nthe increase in specimen length from the point of initial load application to the pointof film rupture in a tension test.3.1.2 gage length, nthe initial length of the test specimen between the jaws of the tensile tester.3.1.3 stiffn
8、ess (modulus of elasticity), nthe load per unit area 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 plot of tensile load against the distance of jaw separation (elongation ofspec
9、imen).3.1.5 tensile strength (nominal), nthe load per original unit 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 are prepared. prepared in accordance with Test Method D4708. Thetensile properties o
10、f the free films are determined by means of a tensile testing apparatus.1 This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.C
11、urrent edition approved Dec. 1, 2010July 1, 2016. Published December 2010November 2016. Originally approved in 1965. Last previous edition approved in 20022010as D2370 98 (2002)(2010).1. DOI: 10.1520/D2370-98R10.10.1520/D2370-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or
12、 contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standardsstandards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard
13、 and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases on
14、ly the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 Tensile properties determined by this method are of value
15、in studying the behavior of coatings subjected to environmentalstresses, such as those produced by aging and weathering. (See Refs. (1-10).)45.2 Tensile properties may vary with specimen thickness, method of preparation, gage length, rate of load application, tensiletester response, and type of grip
16、s used. Consequently, where precise comparative results are desired, these factors must be carefullycontrolled.6. Apparatus6.1 Equipment for applying films of uniform thickness as described in Practices D823.6.2 Micrometer Film Thickness Gage as described in Test Method D1005.6.3 Tensile Tester of t
17、he constant rate of jaw separation type, equipped with load cells having capacities of 0.2 to 4.4 lb (100to 2000 g),1 to 50 N (0.2 to 10 lb), and equipped with computer with tester controlling software, or optionally an indicating devicesuch as an electronic constant speed chart recorder, a digital
18、device that displays numerical values, or a printer that records thenumerical values. Tensile tester can also be equipped with a video-extensometer and environmental chamber, when higheraccuracy of test is required and testing is conducted at an elevated or low temperature.6.4 Precision Specimen Cut
19、ter having a double blade with a foot to hold the sample in place.place5 or other suitable sharp cutterblade.6.5 Alternative Substrates on which test material can be deposited.6.5.1 Dental Tin Foil, preferably 1 mil (25 m) thick.66.5.2 Sheet of FEP (fluorinated ethylene-propylene),7 preferably 2 mil
20、s (50 m) thick, coated with a dry lubricant.8NOTE 1Other substrates that may be suitable are 10-mil (250-m) thick polyethylene (7), photographic paper (8), polished steel (9), andfluoropolymer coated metal panels.7. Hazards7.1 MercuryMercury is a toxic metallic liquid. Its vapors are extremely hazar
21、dous. Small amounts of spilled mercury canvaporize sufficiently at room temperature to exceed the threshold limit values (TLV) of the vapor. Use with adequate ventilation(in a hood) and clean up spills immediately. Wear gloves when handling mercury. Keep containers closed. Droplets of mercurycan be
22、picked up by using a small glass pipet connected to a suction flask with a rubber hose.7. Test Specimens7.1 The test specimens shall be free films having a width that is between 13 and 25 mm (12 and 1 in. (13 and 25 mm).in.). Nospecimen shall vary by more than 62 % in width along its entire gage len
23、gth. The length shall be at least 2 in. (50 mm)50 mm(2 in.) longer than the gage length selected for the test.7.2 Prepare free films by one of the procedures described in Test Method D4708.8. Calibration8.1 Balance, zero, and calibrate the load weighing and recording system of the tensile tester in
24、accordance with methodsspecified by the manufacturer.8.2 If video-extensometer is used, calibrate instrument according to manufacturers instructions.9. Conditioning9.1 Specimens must be fully dried and cured before testing according to manufacturer specification. Unless otherwise agreedupon between
25、the producer and the user, condition the test specimens for at least 24 h at 73.523 6 3.5F (232C (73.5 6 2C)and 50 % 3.5F) and 50 6 5 % relative humidity and test in the same environment.10. Procedure10.1 Select a mutually agreed upon gage length in the range of 1 to 5 in. (25 to 125 mm).25 to 125 m
26、m (1 to 5 in.).10.2 Prepare 10 test specimens for each material to be evaluated. These specimens should not exhibit any nicks or flaws. flawsand should be inspected under 10 magnification for the presence of potential defects. Measure the thickness of each specimento 60.1 mil (2.5 m)m (0.04 mil) wit
27、h a micrometer in accordance with Test Methods D1005, taking five measurements within4 Boldface numbers in parentheses refer to the list of references at the end of this standard.5 The sole source of supply of the JDC precision cutter known to the committee at this time is the Thwing-Albert Instrume
28、nt Co., 10960 Dutton Rd., Philadelphia, PA19154. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration ata meeting of the responsible technical committee,1 which you may attend.D2370 162the gage
29、 length area. If a video-extensometer is used, apply markings on the sample within the distance of gage length selected.The markings on the sample must be readable by the instrument being used. These will vary between manufacturer and models.The material and method of making the marks must not affec
30、t the characteristics of the sample.10.3 Set the jaw separation of the tensile tester at the gage length selected. Place the test specimen in the grips of the testingmachine, taking care to align the long axis of the specimen with an imaginary line joining the points of attachment of the gripsto the
31、 machine. Tighten the grips evenly and firmly to the degree necessary to minimize slipping of the specimen during test.NOTE 1Mounting is facilitated by the use of air activated jaws. Line-type jaws will minimize slippage and breakage. The application ofpressure-sensitive cloth to the ends of the fil
32、m can improve jaw grip. Special self-tightening grips designed to be used with thin films could also be used.10.4 Select a mutually agreed upon rate of elongation (strain rate) that is in the range of 5 to 100 %min. Set the crosshead speedof the tensile tester to provide this rate for the gage lengt
33、h chosen.NOTE 2Arate of elongation should be selected that is optimum for testing the types of materials to be evaluated. For relatively brittle films, elongationrates of 5 to 20 % are suggested. For relatively extensible films, elongation rates of 50 to 100 % are suggested. (Refer to Test Methods D
34、882 for relationof elongation rate to elongation at break).10.5 Elongate the test specimen until rupture of the film occurs and evaluate the stress-strain curve as follows:10.5.1 Determine the specimen elongation from video-extensometer data or by measuring the increase in jaw separation fromthe poi
35、nt of original load application to the point of rupture.10.5.2 Measure the tensile pull in pounds (kg)Newtons (lb) required to rupture the film.10.5.3 If stiffness is desired, determine the tensile pullstress in pounds (kg) MPa to elongate the film 1 % from the first pointin the stress-strain curve
36、where the slope becomes constant.constant or allow the computer to calculate the appropriate tensilemodulus.10.6 Using the procedures in 11.110.1 11.510.5, run ten test specimens for each material under test.11. Calculations11.1 Allow the computer software to calculate for each specimen elongation a
37、t break (EB), tensile strength at break (TS) andmodulus of elasticity (if desired) from electronically stored test data points.11.2 For If a manually operated tensile tester is used, for each specimen compute the following:11.2.1 The elongation at break E,EB, in percent from the following equation:E
38、BE 5100 SLL D (1)where:L = increase in specimen length to break, andL = initial specimen length (gage length).where:L = increase in specimen length to break, andL = initial specimen length (gage length).11.2.2 The tensile strength, TS, in pounds per square inch,MPa (lb per sq. inch), from the equati
39、on:TS5PR!/TW! (2)where:PR = tensile pull to rupture, N (lb),T = thickness of test specimen, m (in.), andW = width of test specimen, m (in.).where:PR = tensile pull to rupture, lb (kg),T = thickness of test specimen, in. (mm), andW = width of test specimen, in. (mm).11.2.3 The stiffness (modulus of e
40、lasticity), S, from the following equation:S 5PE!/TW! (3)where:PE = pull in Newtons (lb) to elongate the film 1 % from the first point in the stress-strain curve where the slope remains constant,T = thickness of test specimen, m (in.), andW = width of test specimen, m (in.).D2370 163where:PE = pull
41、in pounds (kg) to elongate the film 1 % from the first point in the stress-strain curve where the slope remains constant,T = thickness of test specimen, in. (mm), andW = width of test specimen, in. (mm).11.3 Examine the uniformity of the tensile strength and elongation results obtained for the ten s
42、pecimens measured for amaterial. Choose one of the following procedures for discarding spurious values and calculate the mean of the remaining results:11.3.1 Use the results from those five specimens showing the highest tensile strength in evaluating all three properties,discarding those from the re
43、maining five. This is done on the basis that the expected errors (nicks or flaws in the specimen, breakswithin the jaw, slippage in the jaw, etc.) would all tend to produce results on the low side.11.3.2 Discard the values for those specimens where both the tensile strength and elongation values are
44、 significantly lower thanthose for most of the specimens. Use the test for outliers given in Practice D3980 88.12. Report12.1 Type and manufacturer of the tensile tester and extensometer, as well as the software that controls the instrument.12.2 Produce stress-strain curves for all tested specimens
45、(if instrumentation used allows).12.3 Report the mean average dimensions: thickness and width of each specimen and values obtained with the test specimensfor:12.3.1 Tensile strength,12.3.2 Elongation, and12.3.3 Stiffness (modulus of elasticity), if desired.12.4 Report the conditions of the test.12.4
46、.1 Procedure for preparation of free films,12.4.2 Rate of elongation in percent per minute,12.4.3 Specimen size (length, width, and thickness),Specimens gage length and grip separation speed.12.4.4 Temperature and relative humidity during test, and treatment, and12.4.5 Aging and treatment given the
47、specimens.13. Precision and Bias13.1 PrecisionAn interlaboratory test of this test method was conducted in which three coatings (representing a brittle film,a film with limited elasticity, and a very elastic film) were tested by five laboratories. The test was conducted with Instron tensiletesters o
48、perated at two elongation rates (10 and 100 %) with a specimen gage length of 2 in. (50 mm)50 mm (2 in.) and specimenthicknesses of 2.5 to 3.5 mils (65 to 90 m).65 to 90 micrometers (2.5 to 3.5 mils). The between laboratory coefficients of variationwere found to be 30 % for percent elongation and 18
49、 % for tensile strength. Based on these coefficients, the following criteriashould be used for judging the acceptability of results at the 95 % confidence level:13.1.1 ReproducibilityTwo results for percent elongation obtained by operators in different laboratories should be consideredsuspect if they differ by more than 118 % of their mean. Two results for tensile strength obtained by operators in differentlaboratories should be suspect if they differ by more than 70 % of their mean.13.2 BiasSince there is no accepted reference material sui
