1、Designation: D5178 98 (Reapproved 2008)D5178 13Standard Test Method forMar Resistance of Organic Coatings1This standard is issued under the fixed designation D5178; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the mar resistance on smooth, flat surfaces. Results are expressed in terms off
3、orce-to-mar films of organic coatings such as paint, varnish, and lacquer when applied to smooth, flat planar panel surfaces.1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematicalconversions to SI units that are provided for informa
4、tion 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 applicability of regulatory
5、limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D609 Practice for Preparation of Cold-Rolled Steel Panels for Testing Paint, Varnish, Conversion Coatings, and Related CoatingProductsD823 Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on
6、 Test PanelsD1005 Test Method for Measurement of Dry-Film Thickness of Organic Coatings Using MicrometersD1186 Test Methods for Nondestructive Measurement of Dry Film Thickness of Nonmagnetic Coatings Applied to a FerrousBase (Withdrawn 2006)3D1400 Test Method for Nondestructive Measurement of Dry F
7、ilm Thickness of Nonconductive Coatings Applied to aNonferrous Metal Base (Withdrawn 2006)3D2691 Method for Microscopical Measurement of Dry Film Thickness of Coatings on Wood Products (Withdrawn 1992)33. Terminology3.1 Definitions:3.1.1 mar resistance, nthe ability of a coating to resist damage cau
8、sed by light abrasion. As just defined, it is a resistance ofthe surface of the coating to permanent deformation, resulting from the application of a dynamic mechanical force.4. Summary of Test Method4.1 The materials under test are applied at uniform thickness to flat panels of uniform surface text
9、ure. After drying/curing, themar resistance is determined by pushing the panels beneath a rounded stylus or loop that is loaded in increasing amounts until thecoating is marred.5. Significance and Use5.1 In some situations, marring of coatings applied to substrates under typical use conditions is un
10、acceptable. This test methodhas been found useful in differentiating the degree of marring of coatings on substrates. It is most useful in providing relativeratings for a series of coated panels exhibiting significant differences in marring.1 This test method is under the jurisdiction of ASTM Commit
11、tee D01 on Paint and 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, 2008May 15, 2013. Published July 2008May 2013. Originally approved in 1991. Last previous edition a
12、pproved in 20022008 D5178 98(2002).(2008). DOI: 10.1520/D5178-98R08.10.1520/D5178-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary p
13、age 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 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
14、technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive,
15、 PO Box C700, West Conshohocken, PA 19428-2959. United States15.2 In a limited laboratory study, meaningful mar results were impossible when powder coatings were tested. The mar marking,that is, scratches, became less perceptible with time. Therefore, powder coatings may not be applicable coatings f
16、or this testmethod.6. Apparatus6.1 Application Equipment, as described in Practices D823.6.2 Film-Thickness Measuring Apparatus, as described in Test Methods D1005, D1186, D1400, or D2691.6.3 Balanced Beam Scrape Adhesion and Mar Tester (Fig. 1 and Fig. 2), consisting of a balanced beam to which is
17、secured aplatform for supporting weights, and a rod at an angle of 45 that holds the scraping loop. The rod shall be set so that the scrapingloop contacts test surfaces directly below the weights. The loop shall be 116-in. (1.6 mm) diameter rod, bent into a “U” shape withan outside radius of 0.128 6
18、 0.002 in. (3.25 6 0.05 mm) and hardened to Rockwell HRC 56 to 58, and shall be a smooth finish.The loop can be either chromium plated, nickel plated, or heat treated polished steel as agreed upon between the purchaser andthe supplier. These testers are adjustable to accommodate flat, metallic, and
19、nonmetallic specimens to 0.5-in. (12-mm) thick and4 to 16 in. (100 to 400 mm) wide and long; the specimen should be at least 12-in. (12-mm) wide.7. Preparation of Specimens7.1 Apply the materials under test to panels of the composition and surface condition on which it is desired to determine marres
20、istance of the coating.The panel material (7.1.1), surface preparation, thickness, and number of coats shall be specified or agreedupon between the seller and the purchaser. Apply coatings and air dry or bake under conditions of humidity and temperaturemutually agreeable to the seller and the purcha
21、ser.7.1.1 The surface of the coating must be hard enough to resist damage by the scraping loop at a load agreed upon between theproducer and the user. If no panel material is specified, use 0.032-in. (0.8-mm) cold-rolled carbon steel prepared in accordance withMethods B or C of Practice D609.8. Cond
22、itioning and Number of Tests8.1 Condition the test panels for at least 48 h at 23 6 2C (73.5 6 3.5F) and 50 6 5 % relative humidity, and test in the sameenvironment, or immediately on removal therefrom, unless otherwise specified or agreed upon by the seller and the purchaser. Testat least two repli
23、cate specimens of each material.9. Procedure9.1 In preparation for using the apparatus, ensure that it is reasonably level and place it so that the weight holder is toward theoperator. This places the beam release on the operators right and allows freedom to move the test specimen manually under the
24、weighted scraping element (loop). Insert the loop into the holder as far as it will go and tighten the clamping screw. Adjust themain bearing support so that the beam is balanced in the horizontal plane when the loop is just touching the specimen surface. Thealignment of the beam should be such that
25、 the end of the loop is over the midline of the movable table.9.2 Raise the beam and lock it in the raised position. Wipe the loop with a clean cloth or chamois. Locate the specimen on thesliding platform against the stop so that the specimen can be moved away from the operator and there is an area
26、at least 3 in. (75mm) long by 12 in. (12 mm) wide on the sample parallel to the horizontal plane through the beam. Place weights on the weightsupport using an initial amount that is estimated to be appropriate for the particular coating. Release the beam and carefully lowerFIG. 1 Balanced Beam Scrap
27、e Adhesion and Mar TesterD5178 132it until the loop rests on the coated test specimen and the full load is applied, then slowly push the sliding platform away fromthe operator at a rate of 14 in. (6 mm)/s for a distance of at least 3 in. (75 mm). If the coating is marred, continue the testing usings
28、uccessively smaller loads (0.5-kg increments) until the coating is not marred. If the coating is not marred by the initial scrape,continue the test using successively larger loads (0.5-kg increments) until the coating is marred or until the maximum load of 10kg has been applied. Use a new area of th
29、e test surface each time a scrape is made.9.3 When the critical load has been approximately located, repeat the test five times at each of three loadings: above, below andat the load determined in the first trial. Apply Use the replicate specimen to apply different loads in random fashion so that al
30、lscrapes at one load arethe same load is not made in succession or on one panel. succession.9.3.1 Periodically examine the loop to ensure that the original smooth surface is intact. If the contacting surface is worn, reversethe loop. When both sides are worn, replace with a new loop.9.4 For each app
31、lied load, tabulate the number of times the coating was marred.10. Report10.1 Report the following information:10.1.1 Load in kilograms at the mar failure end point,10.1.2 Panel material and surface preparation,10.1.3 “U” shape loop surface finish,10.1.4 Dry-film thickness, and10.1.5 Any deviation f
32、rom the specified procedure.11. Precision11.1 PrecisionIf sufficient cooperators can be obtained, an interlaboratory study will be conducted to establish precision.11.2 BiasNo information can be provided on the bias of this test method for measuring mar because no material having anaccepted referenc
33、e value is available.12. Keywords12.1 balanced beam scrape adhesion and mar tester; balanced beam tester; coatings; mar or organic mar resistanceASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of
34、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 is subject to revision at any time by the responsible technical committee and must be reviewed every five
35、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 Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical comm
36、ittee, 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 standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19
37、428-2959,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/).FIG. 2 Balanced Beam Scrape Adhesion and Mar TesterD5178 133
