1、Designation: D 2370 98 (Reapproved 2002)Standard Test Method forTensile Properties of Organic Coatings1This standard is issued under the fixed designation D 2370; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the determination of
3、 the elon-gation, tensile strength, and stiffness (modulus of elasticity) oforganic coatings when tested as free films.1.2 The values stated in inchpound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.3 This standard does not purport to address all
4、 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. Specific hazardstatements are given in Section 7.2. Referenced
5、Documents2.1 ASTM Standards:D 823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test Panels2D 882 Test Methods for Tensile Properties of Thin PlasticSheeting3D 1005 Test Methods for Measurement of Dry-Film Thick-ness of Organic Coatings Using Micrometer
6、s2D 3980 Practice for Interlaboratory Testing of Paint andRelated Materials4D 4708 Practice for Preparation of Uniform Free Films ofOrganic Coatings23. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 elongationthe increase in specimen length from thepoint of initial load applicat
7、ion to the point of film rupture ina tension test.3.1.2 gage lengththe initial length of the test specimenbetween the jaws of the tensile tester.3.1.3 stiffness (modulus of elasticity)the load per unit arearequired to elongate the film 1 % from the first point in thestress-strain curve where the slo
8、pe becomes constant.3.1.4 stress-strain curvethe curve resulting from a plot oftensile load against the distance of jaw separation (elongationof specimen).3.1.5 tensile strength (nominal)the load per original unitarea at which a specimen fails or yields in a tension (pull) test.4. Summary of Test Me
9、thod4.1 Free unsupported films of the materials to be tested areprepared. The tensile properties of the free films are determinedby means of a tensile testing apparatus.5. Significance and Use5.1 Tensile properties determined by this method are ofvalue in studying the behavior of coatings subjected
10、to envi-ronmental stresses, such as those produced by aging andweathering. (See Refs. (1-10).)55.2 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
11、results are desired, these factorsmust be carefully controlled.6. Apparatus6.1 Equipment for applying films of uniform thickness asdescribed in Practices D 823.6.2 Micrometer Film Thickness Gage as described in TestMethod D 1005.6.3 Tensile Tester of the constant rate of jaw separationtype, equipped
12、 with load cells having capacities of 0.2 to 4.4 lb(100 to 2000 g), and equipped with an indicating device suchas an electronic constant speed chart recorder, a digital devicethat displays numerical values, or a printer that records thenumerical values.1This test method is under the jurisdiction of
13、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 Dec. 10, 1998. Published February 1999. Originallypublished as D 2370 65 T. Last previous edition
14、 D 2370 92.2Annual Book of ASTM Standards, Vol 06.01.3Annual Book of ASTM Standards, Vol 08.01.4Discontinued 1998; see 1997 Annual Book of ASTM Standards, Vol 06.01.5Boldface numbers in parentheses refer to the list of references at the end of thisstandard.1Copyright ASTM International, 100 Barr Har
15、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.4 Precision Specimen Cutter having a double blade witha foot to hold the sample in place.66.5 Alternative Substrates on which test material can bedeposited.6.5.1 Dental Tin Foil, preferably 1 mil (25 m) thick.76.5.2 Sheet of F
16、EP (fluorinated ethylene-propylene),8pref-erably 2 mils (50 m) thick, coated with a dry lubricant.9NOTE 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
17、toxic metallic liquid. Its vaporsare extremely hazardous. Small amounts of spilled mercurycan vaporize sufficiently at room temperature to exceed thethreshold limit values (TLV) of the vapor. Use with adequateventilation (in a hood) and clean up spills immediately. Weargloves when handling mercury.
18、Keep containers closed. Drop-lets of mercury can be picked up by using a small glass pipetconnected to a suction flask with a rubber hose.8. Test Specimens8.1 The test specimens shall be free films having a widththat is between12 and 1 in. (13 and 25 mm). No specimen shallvary by more than 62 % in w
19、idth along its entire length. Thelength shall be at least 2 in. (50 mm) longer than the gagelength selected for the test.8.2 Prepare free films by one of the procedures described inTest Method D 4708.9. Calibration9.1 Balance, zero, and calibrate the load weighing andrecording system of the tensile
20、tester in accordance withmethods specified by the manufacturer.10. Conditioning10.1 Unless otherwise agreed upon between the producerand the user, condition the test specimens for at least 24 h at73.5 63.5F (23 62C) and 50 % relative humidity and test inthe same environment.11. Procedure11.1 Select
21、a mutually agreed upon gage length in the rangeof 1 to 5 in. (25 to 125 mm).11.2 Prepare 10 test specimens for each material to beevaluated. These specimens should not exhibit any nicks orflaws. Measure the thickness of each specimen to 60.1 mil (2.5m) with a micrometer in accordance with Test Metho
22、dsD 1005, taking five measurements within the gage length area.11.3 Set the jaw separation of the tensile tester at the gagelength selected. Place the test specimen in the grips of thetesting machine, taking care to align the long axis of thespecimen with an imaginary line joining the points of atta
23、ch-ment of the grips to the machine. Tighten the grips evenly andfirmly to the degree necessary to minimize slipping of thespecimen during test.NOTE 2Mounting is facilitated by the use of air activated jaws.Line-type jaws will minimize slippage and breakage. The application ofpressure-sensitive clot
24、h to the ends of the film can improve jaw grip.11.4 Select a mutually agreed upon rate of elongation (strainrate) that is in the range of 5 to 100 %/min. Set the crossheadspeed of the tensile tester to provide this rate for the gagelength chosen.NOTE 3A rate of elongation should be selected that is
25、optimum fortesting the types of materials to be evaluated. For relatively brittle films,elongation rates of 5 to 20 % are suggested. For relatively extensible films,elongation rates of 50 to 100 % are suggested. (Refer to Test MethodsD 882 for relation of elongation rate to elongation at break).11.5
26、 Elongate the test specimen until rupture of the filmoccurs and evaluate the stress-strain curve as follows:11.5.1 Determine the specimen elongation by measuring theincrease in jaw separation from the point of original loadapplication to the point of rupture.11.5.2 Measure the tensile pull in pounds
27、 (kg) required torupture the film.11.5.3 If stiffness is desired, determine the tensile pull inpounds (kg) to elongate the film 1 % from the first point in thestress-strain curve where the slope becomes constant.11.6 Using the procedures in 11.1-11.5, run ten test speci-mens for each material under
28、test.12. Calculations12.1 For each specimen compute the following:12.1.1 The elongation E, in percent from the followingequation:E 5 100SDLLD(1)where:DL = increase in specimen length to break, andL = initial specimen length (gage length).12.1.2 The tensile strength, TS, in pounds per square inch,fro
29、m the equation:TS 5 PR!/TW! (2)where:PR= tensile pull to rupture, lb (kg),T = thickness of test specimen, in. (mm), andW = width of test specimen, in. (mm).12.1.3 The stiffness (modulus of elasticity), S, from thefollowing equation:6The sole source of supply of the JDC precision cutter known to the
30、committeeat this time is the Thwing-Albert Instrument Co., 10960 Dutton Rd., Philadelphia,PA 19154. If you are aware of alternative suppliers, please provide this informationto ASTM International Headquarters. Your comments will receive careful consid-eration at a meeting of the responsible technica
31、l committee,1, which you may attend.7Dental tin foil is suitable for this purpose.8Teflon FEP 2-mil film thickness (Card No. 03111, Item #29499) from E. I. duPont de Nemours organic coatings; stiffness; tensile proper-ties; tensile strengthREFERENCES(1) Ashton, H. E., “Flexibility and Its Retention
32、in Clear CoatingsExposed to Weathering,” Journal of Coatings Technology, Vol 51, No.653, June 1979, pp. 4152.(2) Ashton, H. E., “Predicting Durability of Clear Finishes for Wood fromBasic Properties,” Journal of Coatings Technology, Vol 52, No. 663,April 1980, pp. 6371.(3) Beardsley, Herbert P., and
33、 Kennedy, Richard J., “Performance ofExterior Paints Based on a Vinyl Acetate-Ethylene Emulsion Vehicle,”Journal of Paint Technology, Vol 39, No. 505, February 1967, pp.8898.(4) Evans, Robert M., and Fogel, Joseph,“ Comparison of Tensile andMorphological Properties With Abrasion Resistance of Uretha
34、neFilms,” Journal of Coatings Technology, Vol 49, No. 634, November1977, pp. 5060.(5) Holsworth, Richard M., Provder, Theodore, and Ranig, Alexander, Jr.,“Physical Characterization of Coatings Upon Aging,” Journal of PaintTechnology, Vol 46, No. 596, September 1974, pp. 7695.(6) Levine, Eli, Lindlaw
35、, William, and Vona, Joseph A., “Some RecentDevelopments in Water-Based Systems,” Journal of Paint Technology,Vol 41, No. 537, October 1969, pp. 531536.(7) Pierce, Percy E., and Holsworth, Richard M., “The MechanicalProperties and Performance of Wood Primers,” Journal of PaintTechnology, Vol 38, No.
36、 501, October 1966, pp. 584590.(8) Shur, E. G., and Rubin, H., “Accelerated Testing of Finishes ForHardboard,” Journal of Paint Technology, Vol 41, No. 537, October1969, pp. 537550.(9) Schurr, Garmond G., Hay, T. Kirk, and Van Loo, Maurice, “Possibilityof Predicting Exterior Durability by Stress/Str
37、ain Measurements,”Journal of Paint Technology, Vol 38, No. 501, October 1966, pp.591599.(10) Yaseen, M., and Ashton H. E., “Effect of Free Film PreparationMethod on Organic Coatings,” Journal of Coatings Technology,Vol49, No. 629, June 1977, pp. 5058.D 23703ASTM International takes no position respe
38、cting 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 st
39、andard 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 Internat
40、ional 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 belo
41、w.This 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).D 23704
