1、Designation: D6279 03 (Reapproved 2013)D6279 15Standard 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, th
2、e 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.1. Scope1.1 This test method covers procedures for evaluating the relative mar resistance of a series of high gloss coat
3、ings applied toa flat, rigid surface. Wet rub and dry rub abrasion tests are described. To fully characterize a coatings mar resistance, both testsshould be run.NOTE 1Dry abrasion mar resistance can also be evaluated by using Test Methods D6037. If a series of very highly mar resistant coatings is b
4、eingevaluated, Test Methods D6037 will generally provide the better performance discrimination than the dry rub test described here. However, if theequipment described in Test Methods D6037 is not available, the dry rub test described in this test method affords a reasonable alternative. The dry rub
5、test is also useful for evaluating coatings that are not highly mar resistant.1.2 Mar resistance is assessed by measuring the gloss of the abraded and unabraded areas. Mar resistance is directly related tothe coatings ability to retain gloss in abraded areas.NOTE 2The mar resistance values obtained
6、by this test method have no absolute significance. They should only be used to derive relative performancerankings for test panels that have been prepared from the series of coatings that are currently being evaluated. If mar resistance values are quoted betweenlaboratories, it is essential that a c
7、ommon standard be measured and that the values be compared to that standard. Even then, the values should be usedwith caution.1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.1.4 This standard does not purport to address the s
8、afety concerns, if any, associated with its use. It is the responsibility of theuser of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitationsprior to use.2. Referenced Documents2.1 ASTM Standards:2D523 Test Method for Specular Gl
9、ossD823 Practices for Producing Films of Uniform Thickness of Paint, Varnish, and Related Products on 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 Coating
10、s Applied to a FerrousBase (Withdrawn 2006)3D1400 Test Method for Nondestructive Measurement of Dry Film Thickness of Nonconductive Coatings Applied to aNonferrous Metal Base (Withdrawn 2006)3D3924 Specification for Environment for Conditioning and Testing Paint, Varnish, Lacquer, and Related Materi
11、alsD6037 Test Methods for Dry Abrasion Mar Resistance of High Gloss Coatings3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 mar resistance, nthe ability of a coating to resist permanent deformation or fracture, resulting from the application ofa dynamic mechanical force.3.1.1.
12、1 Discussion1 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 D01.55 on Factory Applied Coatings on Preformed Products.Current edition approved June 1, 2013Dec. 1, 2015. Publis
13、hed July 2013January 2016. Originally approved in 1998. Last previous edition approved in 20072013 asD6279 03 (2007).(2013). DOI: 10.1520/D6279-03R13.10.1520/D6279-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual B
14、ook 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 and is intended only to provide the user of an ASTM standard
15、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 only the current versionof the standard as published by ASTM is
16、to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1This test method measures resistance to visible damage caused by mild abrasion.4. Summary of Test Method4.1 The coatings that are being evaluated a
17、re applied at uniform dry film thickness to planar panels of uniform surface texture.After drying or curing, or both, panels are marred by the action of dry abrasion media or wet abrasion media, or both, under areciprocating weighted pad. Mar resistance is assessed by measuring the coatings gloss wi
18、thin the abraded and unabraded areasof test panels. Mar resistance is directly related to the coatings ability to retain gloss in abraded areas.5. Significance and Use5.1 Coatings, particularly the high gloss coatings used on automobiles, boats, toys, etc., are subject of a wide variety ofconditions
19、 (for example, wiping, cleaning and exposure) during manufacture and service that can mar their surface. The ability ofhigh gloss coatings to maintain their appearance is an important product attribute. This test method provides a way to estimate theability of high gloss coatings to resist mar damag
20、e.6. Apparatus6.1 Application Equipment, as described in Practices D823.6.2 Film Thickness Measuring Apparatus, as described in Test Methods D1005, D1186 or D1400.6.3 AbraderThe mar tester4 is so designed that the 16 mm, 61 mm diameter, friction element with a downward force of 9N, 610 %, moves back
21、 and forth in a straight line over a 100 mm 6 10 mm (4 in 6 0.4 in.) track on the test panel. It has a uniformstroke rate of 60 r/min. One revolution is a complete back and forth motion.6.4 Friction PadCover the instruments friction element with a pad made of felt or paper. Felt pads can be attached
22、 bywrapping the felt around the friction element and holding it in place with a suitable spring clip or clamp. Paper pads must be cutto fit to cover the area of the friction element that contacts the coating. They can be attached to the friction element with two-sidedtape or paper pads that can be p
23、urchased with an adhesive backing. The type of pad affects the abrasion and so must be definedfor the test. It has been found that generally a thicker felt pad works best for dry abrasion and a thinner pad is best for wet abrasion.6.5 Dry Abrasion MediaFeldspar/calcite, non-silicate cleaning powder.
24、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 a mixer or spatula. The slurry gets very thick, but is easy t
25、o mix.6.6.2 The slurry prepared by this formula should have a pH of 7.9 to 8.0 and a viscosity of 190 to 210 P (as measured on aBrookfield Viscometer, No. 4 spindle, rotational viscometer with a spindle that is a right circular cylinder 3.2 mm in diameter and31.0 mm in length, 10 r/min). If the pH a
26、nd viscosity are low, add 2-aminopropanol until the pH is 7.9 to 8.0. If the pH is on targetbut the viscosity is low, add more polyacrylic acid.7. Preparation of Specimens7.1 Prepare a minimum of two (2) 101.6 by 152.4-mm (4 by 6-in.) panels for each coating that is being tested. Alternatively,if th
27、e abrasion apparatus can accommodate them, 101.6 by 304.8-mm (4 by 12-in.) panels may be used. Prepare the coated panelsas described in Practices D823.7.2 Gloss measurements are color dependent. Abraded areas on dark colored panels tend to give lower gloss readings thansimilarly abraded areas on lig
28、ht colored panels. For consistent results, it is recommended that testing be done using black coatings.Clearcoats can be applied over a black basecoat. If it is necessary to use other colors, a black panel should be included as a control.8. Conditioning8.1 Condition the test specimens at 23 6 2C (74
29、 6 4F) and 50 6 5 % relative humidity in accordance with SpecificationD3924 unless otherwise specified in the test methods or the standard.9. Procedure9.1 Securely fasten the friction element to the reciprocating arm.9.2 Set the number of cycles at 10, unless otherwise specified. Set fewer cycles fo
30、r easily marred panels and more cycles formore mar resistant materials.4 A list of machines suitable for this purpose is found in Research Report RR:D01-1117. Contact ASTM Customer Service at serviceastm.org.D6279 1529.3 Attach a new pad to the friction element. If an adhesive backed pad is used, at
31、tach the pad to the bottom of the frictionelement. For nonadhesive backed pads, cover the friction element by cupping the cloth around the bottom.Attach the material witha spring clip or clamp, such that a flat, unwrinkled cloth surface comes into contact with the coated panel.9.4 Dry AbrasionSprink
32、le a liberal amount of dry abrasion media over approximately one half of the panel. Holding the panelso its plane is vertical, tap its bottom edge firmly on a hard surface so that an even, thin layer of dry adhesion media remains onthe panel. Place the test panel in the apparatus.9.5 Wet AbrasionPla
33、ce the test panel on the test area and secure. Spread wet abrasion media on the pad using a spatula to coverthe pad well. Lower the friction element to the panel. Excess media should be visible on all sides of the friction element. Thisindicates full coverage of the friction pad. Ensure that the fri
34、ction pad lies flat on the panel.9.6 For both wet and dry abrasion start the test and run the selected 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 can be repeated by replacing the pad and using an unmarred area of thecleans
35、er-coated panel. The wet test can be repeated by replacing the pad, applying the slurry, and then moving the panel so thatthe friction element is on an unmarred area.9.9 Remove the panel, rinse with water, and pat dry with a soft cloth or paper towel.9.10 Using a glossmeter with 20 geometry that has
36、 been properly adjusted, in accordance with Test Method D523, measurethe gloss at four (4) places within the unabraded areas of the coated panel. Measure the gloss in the same direction that will beused in 9.11. Record the mean of these four readings as “Unabraded Gloss.”9.11 Measure the 20 gloss at
37、 four (4) places within the abraded areas of the coated panel (measure the gloss perpendicular tothe abrasion grooves). To compensate for unevenness in the abrasion pattern, it is desirable to adjust the measurement position toget the four lowest gloss readings within the abraded area. Record the me
38、an of the four readings as the “Abraded Gloss.”D6279 153NOTE 3Subjective comparisons may be made by visually comparing abraded panels with a previously prepared abraded standard. Do not use areasat the ends or edges of the abrasion pattern since they are not representative of the average abrasion. O
39、ptical imaging measurements can also be usedto obtain quantitative evaluation of the abrasion.NOTE 4Small differences in performance between highly abrasion resistant materials are more likely to detected with 20 gloss measurements thanwith 60 gloss measurements.10. Calculation10.1 Calculate the per
40、cent gloss retention for each panel as follows:%Gloss Retention51003Abraded Gloss/Unabraded Gloss! (1)NOTE 5Abraded and unabraded gloss is the grand mean calculated from the means obtained (in accordance with 9.10 and 9.11) for each of the panelsused to test a particular coating.11. Report11.1 Repor
41、t the following information:11.1.1 The identity of the monocoat or the basecoat/clearcoat that was used, the bake schedule, film thickness and color,11.1.2 A description of the type of friction pad used, the type of abrading media used, and the number of abrasion cycles,11.1.3 The type of mar test t
42、hat was used, that is, wet or dry abrasion,11.1.4 The percent gloss retention mar resistance values that were obtained for each coating in the series,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 retenti
43、on values that were obtained versus the number of abrasion cycles, if more than oneabrasion cycle was used.12. Precision and Bias512.1 PrecisionIt is not practical to specify precision because, as stated in Note 2, the values obtained by this test method haveno absolute value and should only be used
44、 to derive relative performance rankings for test panels. Because of this, no statementson Repeatability and Reproducibility are being made.12.2 BiasSince there is no accepted reference procedure suitable for determining the bias for this test method, no statementon bias is being made.13. Keywords13
45、.1 abrasion; aluminum; coatings; gloss; grit; mar; powder; rub test; scratchASTM International takes no position respecting 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 validit
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49、s) 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ Supporting data are available from ASTM International Headquarters. Request RR:D01-1117. Contact ASTM Customer Service at serviceastm.org.D6279 154
