1、Designation: D6279 03 (Reapproved 2013)Standard Test Method forRub Abrasion Mar Resistance of High Gloss Coatings1This standard is issued under the fixed designation D6279; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f last revision. 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 procedures for evaluating therelative mar resistance of a series of high gloss coatings appl
3、iedto a flat, rigid surface. Wet rub and dry rub abrasion tests aredescribed. To fully characterize a coatings mar resistance,both tests should be run.NOTE 1Dry abrasion mar resistance can also be evaluated by usingTest Methods D6037. If a series of very highly mar resistant coatings isbeing evaluat
4、ed, Test Methods D6037 will generally provide the betterperformance discrimination than the dry rub test described here. However,if the equipment described in Test Methods D6037 is not available, the dryrub test described in this test method affords a reasonable alternative. Thedry rub test is also
5、useful for evaluating coatings that are not highly marresistant.1.2 Mar resistance is assessed by measuring the gloss of theabraded and unabraded areas. Mar resistance is directly relatedto the coatings ability to retain gloss in abraded areas.NOTE 2The mar resistance values obtained by this test me
6、thod haveno absolute significance. They should only be used to derive relativeperformance rankings for test panels that have been prepared from theseries of coatings that are currently being evaluated. If mar resistancevalues are quoted between laboratories, it is essential that a commonstandard be
7、measured and that the values be compared to that standard.Even then, the values should be used with caution.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address the safetyconcerns, if an
8、y, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D523 Test Method for Specular GlossD823 Practices for
9、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 MicrometersD1186 Test Methods for Nondestructive Measurement ofDry Film Thickness of Nonmagnetic Coatings Applied toa Ferrous B
10、ase (Withdrawn 2006)3D1400 Test Method for Nondestructive Measurement of DryFilm Thickness of Nonconductive Coatings Applied to aNonferrous Metal Base (Withdrawn 2006)3D3924 Specification for Environment for Conditioning andTesting Paint, Varnish, Lacquer, and Related MaterialsD6037 Test Methods for
11、 Dry Abrasion Mar Resistance ofHigh Gloss Coatings3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 mar resistance, nthe ability of a coating to resistpermanent deformation or fracture, resulting from the applica-tion of a dynamic mechanical force.3.1.1.1 DiscussionThis test met
12、hod measures resistance tovisible damage caused by mild abrasion.4. Summary of Test Method4.1 The coatings that are being evaluated are applied atuniform dry film thickness to planar panels of uniform surfacetexture. After drying or curing, or both, panels are marred bythe action of dry abrasion med
13、ia or wet abrasion media, orboth, under a reciprocating weighted pad. Mar resistance isassessed by measuring the coatings gloss within the abradedand unabraded areas of test panels. Mar resistance is directlyrelated to the coatings ability to retain gloss in abraded areas.5. Significance and Use5.1
14、Coatings, particularly the high gloss coatings used onautomobiles, boats, toys, etc., are subject of a wide variety ofconditions (for example, wiping, cleaning and exposure) dur-ing manufacture and service that can mar their surface. Theability of high gloss coatings to maintain their appearance is
15、animportant product attribute. This test method provides a way toestimate the ability of high gloss coatings to resist mar damage.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommitte
16、e D01.55 on Factory Applied Coatings on Preformed Products.Current edition approved June 1, 2013. Published July 2013. Originally approvedin 1998. Last previous edition approved in 2007 as D6279 03 (2007). DOI:10.1520/D6279-03R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org,
17、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.Copyright ASTM International, 100 Barr Harbor D
18、rive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Apparatus6.1 Application Equipment, as described in Practices D823.6.2 Film Thickness Measuring Apparatus, as described inTest Methods D1005, D1186 or D1400.6.3 AbraderThe mar tester4is so designed that the 16 mm,61 mm diameter, f
19、riction element with a downward force of 9N, 610 %, moves back and forth in a straight line over a 100mm 6 10 mm (4 in 6 0.4 in.) track on the test panel. It has auniform stroke rate of 60 r/min. One revolution is a completeback and forth motion.6.4 Friction PadCover the instruments friction element
20、with a pad made of felt or paper. Felt pads can be attached bywrapping the felt around the friction element and holding it inplace with a suitable spring clip or clamp. Paper pads must becut to fit to cover the area of the friction element that contactsthe coating. They can be attached to the fricti
21、on element withtwo-sided tape or paper pads that can be purchased with anadhesive backing. The type of pad affects the abrasion and somust be defined for the test. It has been found that generally athicker felt pad works best for dry abrasion and a thinner padis best for wet abrasion.6.5 Dry Abrasio
22、n MediaFeldspar/calcite, non-silicatecleaning powder.6.6 Wet Abrasion MediaPrepare an aluminum oxide (grit)slurry as follows:aluminum oxide (220 mesh) 10.0 (by weight)polyacrylic acid 6.0distilled water 83.32-aminopropanol 0.7Total 100.06.6.1 The slurry ingredients can be combined by using amixer or
23、 spatula. The slurry gets very thick, but is easy to mix.6.6.2 The slurry prepared by this formula should have a pHof 7.9 to 8.0 and a viscosity of 190 to 210 P (as measured ona Brookfield Viscometer, No. 4 spindle, 10 r/min). If the pHand viscosity are low, add 2-aminopropanol until the pH is 7.9to
24、 8.0. If the pH is on target but the viscosity is low, add morepolyacrylic acid.7. Preparation of Specimens7.1 Prepare a minimum of two (2) 101.6 by 152.4-mm (4 by6-in.) panels for each coating that is being tested.Alternatively,if the abrasion apparatus can accommodate them, 101.6 by304.8-mm (4 by
25、12-in.) panels may be used. Prepare the coatedpanels as described in Practices D823.7.2 Gloss measurements are color dependent.Abraded areason dark colored panels tend to give lower gloss readings thansimilarly abraded areas on light colored panels. For consistentresults, it is recommended that test
26、ing be done using blackcoatings. Clearcoats can be applied over a black basecoat. If itis necessary to use other colors, a black panel should beincluded as a control.8. Conditioning8.1 Condition the test specimens at 23 6 2C (74 6 4F)and 50 6 5 % relative humidity in accordance with Specifica-tion D
27、3924 unless otherwise specified in the test methods orthe standard.9. Procedure9.1 Securely fasten the friction element to the reciprocatingarm.9.2 Set the number of cycles at 10, unless otherwisespecified. Set fewer cycles for easily marred panels and morecycles for more mar resistant materials.9.3
28、 Attach a new pad to the friction element. If an adhesivebacked pad is used, attach the pad to the bottom of the frictionelement. For nonadhesive backed pads, cover the frictionelement by cupping the cloth around the bottom. Attach thematerial with a spring clip or clamp, such that a flat, un-wrinkl
29、ed cloth surface comes into contact with the coatedpanel.9.4 Dry AbrasionSprinkle a liberal amount of dry abra-sion media over approximately one half of the panel. Holdingthe panel so its plane is vertical, tap its bottom edge firmly ona hard surface so that an even, thin layer of dry adhesion media
30、remains on the panel. Place the test panel in the apparatus.9.5 Wet AbrasionPlace the test panel on the test area andsecure. Spread wet abrasion media on the pad using a spatulato cover the pad well. Lower the friction element to the panel.Excess media should be visible on all sides of the frictione
31、lement. This indicates full coverage of the friction pad. Ensurethat the friction pad lies flat on the panel.9.6 For both wet and dry abrasion start the test and run theselected number of cycles.9.7 Lift the arm from the panel and discard the pad.9.8 Repeat the mar test at least once. The dry test c
32、an berepeated by replacing the pad and using an unmarred area ofthe cleanser-coated panel. The wet test can be repeated byreplacing the pad, applying the slurry, and then moving thepanel so that the friction element is on an unmarred area.9.9 Remove the panel, rinse with water, and pat dry with asof
33、t cloth or paper towel.9.10 Using a glossmeter with 20 geometry that has beenproperly adjusted, in accordance with Test Method D523,measure the gloss at four (4) places within the unabraded areasof the coated panel. Measure the gloss in the same directionthat will be used in 9.11. Record the mean of
34、 these fourreadings as “Unabraded Gloss.”9.11 Measure the 20 gloss at four (4) places within theabraded areas of the coated panel (measure the gloss perpen-dicular to the abrasion grooves). To compensate for unevennessin the abrasion pattern, it is desirable to adjust the measurementposition to get
35、the four lowest gloss readings within theabraded area. Record the mean of the four readings as the“Abraded Gloss.”4A list of machines suitable for this purpose is found in Research ReportRR:D01-1117.D6279 03 (2013)2NOTE 3Subjective comparisons may be made by visually comparingabraded panels with a p
36、reviously prepared abraded standard. Do not useareas at the ends or edges of the abrasion pattern since they are notrepresentative of the average abrasion. Optical imaging measurements canalso be used to obtain quantitative evaluation of the abrasion.NOTE 4Small differences in performance between hi
37、ghly abrasionresistant materials are more likely to detected with 20 gloss measure-ments than with 60 gloss measurements.10. Calculation10.1 Calculate the percent gloss retention for each panel asfollows:% Gloss Retention 5 100 3 Abraded Gloss/Unabraded Gloss! (1)NOTE 5Abraded and unabraded gloss is
38、 the grand mean calculatedfrom the means obtained (in accordance with 9.10 and 9.11) for each ofthe panels used to test a particular coating.11. Report11.1 Report the following information:11.1.1 The identity of the monocoat or the basecoat/clearcoat that was used, the bake schedule, film thickness
39、andcolor,11.1.2 A description of the type of friction pad used, thetype of abrading media used, and the number of abrasioncycles,11.1.3 The type of mar test that was used, that is, wet or dryabrasion,11.1.4 The percent gloss retention mar resistance values thatwere obtained for each coating in the s
40、eries,11.1.5 The number of mar tests that were run on each panel,11.1.6 The number of panels that were tested, and11.1.7 A plot of the percent gloss retention values that wereobtained versus the number of abrasion cycles, if more thanone abrasion cycle was used.12. Precision and Bias512.1 PrecisionI
41、t is not practical to specify precisionbecause, as stated in Note 2, the values obtained by this testmethod have no absolute value and should only be used toderive relative performance rankings for test panels. Becauseof this, no statements on Repeatability and Reproducibility arebeing made.12.2 Bia
42、sSince there is no accepted reference proceduresuitable for determining the bias for this test method, nostatement on bias is being made.13. Keywords13.1 abrasion; aluminum; coatings; gloss; grit; mar; pow-der; rub test; scratchASTM International takes no position respecting the validity of any pate
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45、nts 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 standard is copyrighted
46、 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/).5Supporting data are available from ASTM International Headquarters. RequestRR:D01-1117.D6279 03 (2013)3
