1、Designation: D2486 06 (Reapproved 2016)D2486 17Standard Test Methods forScrub Resistance of Wall Paints1This standard is issued under the fixed designation D2486; 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 () 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 These test methods cover a procedure for
3、 determining the resistance of wall paints to erosion caused by scrubbing, referredto herein after as “scrub resistance.”1.2 Two test methods are covered as follows:1.2.1 Test Method ACycles-to-failure obtained on test paint.1.2.2 Test Method BRatio expressed as a percentage of cycles-to-failure obt
4、ained on the test paint to that obtained on aconcurrent run with a known reference paint.1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, as
5、sociated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principle
6、s on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D3924 Specification for Environment fo
7、r Conditioning and Testing Paint, Varnish, Lacquer, and Related Materials (Withdrawn2016)3D4213 Test Method for Scrub Resistance of Paints by Abrasion Weight Loss3. Summary of Test Method3.1 In Test Method A, the test paint is applied to a black plastic panel. After curing, the coated panel is place
8、d over a 12.7 wideby 0.25-mm thick (12-in. by 10-mil) shim and held in place on a drawdown plate in a washability machine by means of a gasketedframe. The coated panel is then scrubbed with a bristle brush and an abrasive scrub medium until the paint film is removed in onecontinuous thin line across
9、 the shim.3.2 In Test Method B, the test paint and a reference paint are applied simultaneously perpendicular to the length of the blackplastic panel. After curing, the coated panel is placed over two 12.7 by 0.25-mm (12-in. by 10-ml) shims that are positioned undereach coating. The coatings are the
10、n scrubbed with a bristle brush and an abrasive scrub medium until each paint film is removedin one continuous thin line across its own shim.4. Significance and Use4.1 Paints often become soiled, especially near doorways, windows, and in work and play areas. These test methods cover thedetermination
11、 of the relative resistance of different paints to erosion when repeatedly scrubbed during the life of the paint.1 These test methods are under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and are the direct responsibility ofSubcommittee D01.42 on
12、 Architectural Coatings.Current edition approved Dec. 1, 2016June 1, 2017. Published December 2016July 2017. Originally approved in 1966. Last previous edition approved in 20122016 asD2486 06 (2012)(2016).1. DOI: 10.1520/D2486-06R16.10.1520/D2486-17.2 For referencedASTM standards, visit theASTM webs
13、ite, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards 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 A
14、STM 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 technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In
15、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, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 Test Method D4213 is a similar scrub resistance test using a weight-l
16、oss technique and reporting volumetric film erosionrates.4.3 Test Method A measures scrub resistance by the traditional cycles-to-failure concept. Poor correlation in scrub testing canbe attributable to among other things variations in the stiffness of the brush bristles, condition of washability te
17、ster, application anddrying conditions. In an attempt to improve reproducibility, Test Method B has been developed.5. Apparatus5.1 Straight Line Washability Machine.5.1.1 Accessory Apparatus: (see Figs. 1 and 2).5.1.1.1 Nylon Bristle Brush and Accessories, (total weight 454 6 10 g).5.1.1.2 Drawdown
18、Plate, 454 by 165 by 6.3 mm (1778 by 612 by 14 in.).5.1.1.3 Brass Shims, 12.7- by 0.25-mm (12-in. by 10-mils). Its length can be fitted to the width of the drawdown plate.5.2 Film Applicator, having 0.18-mm (7-mil) clearance and 6.25-mm (14-in.) edge and width of 135 mm (514-in.).6. Reagents and Mat
19、erials6.1 Purity of ReagentsReagent grade chemicals shall be used in all tests.6.2 Black Plastic Panels. 4,56.3 Abrasive Scrub Medium. 5,64 Dull black plastic panels, P-121-10N, 165 by 432 by 0.25 mm (6 12 by 17 in. by 10 mils) manufactured by The Leneta Co., 15 Whitney Rd., Mahwah, NJ 07430 wereuse
20、d in the original development of this standard in order to get the results in these test methods.5 If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical
21、committee,1 which you may attend.6 The sole source of supply of the abrasive scrub medium known to the committee at this time is The Leneta Company.FIG. 1 Accessory Apparatus for Scrub TestD2486 1726.3.1 Laboratory standardized abrasive scrub medium consisting of the following:gramsWater, distilled
22、or deionized 49.4AHydroxyethyl cellulose5,7 0.8Ammonium hydroxide, 28 % 0.1Detergent5,8 2.0Trisodium phosphate, anhydrous 2.0Silica5,9 45.0Acetic acid (glacial) 0.7BPreservative5,10 0.03gA Adjust to achieve viscosity of 110 to 120 Krebs units before use.B Vary to achieve a pH of 9.5 to 10.6.4 Refere
23、nce paint when using Test Method B.7. Preparation of Apparatus7.1 Washability MachineThe straight line washability machine should be leveled before use and operated at 37 6 1 cyclesper minute.7.2 BrushReplace the brush when the bristles have become worn to a point that the bristles extend less than
24、15 mm (58 in.)from the block. Mark the ends of the brush to ensure it is oriented in the same direction for each use.7 Cellosize QP-4400H, The Dow Chemical Company, Midland, Michigan, was used in developing the Precision and Bias statement. Other equivalent molecular weightcellulosic thickeners can
25、be used such as Natrosol 250 MR, Ashland Aqualon, Wilmington, Delaware.8 The sole source of supply of the Triton X-100 detergent known to the committee at this time is The Dow Chemical Company, Midland, Michigan.9 The sole source of supply of the Imsil 45 known to the committee at this time is follo
26、wing silica is recommended by this Subcommittee and is used in commerciallyavailable abrasive scrub media. It is also known to be used by companies who blend their own abrasive scrub media: Imsil 1240, manufactured by Unimin Specialty MineralsInc., 258 Elm St., New Canaan, CT 06840.10 The preservati
27、ve package recommended is BIT, 1,2Benzisothiazol-3(2H)-one. There are several suppliers who offer BIT-based agents.FIG. 2 Accessory Apparatus for Scrub TestD2486 1737.2.1 Brushes (that are in frequent use)Brushes that are in frequent use shall be stored in water. Each time before starting thefirst t
28、est of the day, remove the brush and rinse in water, then precondition the brush, by running it for 400 cycles on a scrub panel,after which it is ready for test work.7.2.2 Brushes (that are not in regular use)Brushes that will not be used on a regular basis shall be washed out thoroughly inwater aft
29、er their last use and stored with the bristling side up under ambient conditions. Before being used again, the brush shouldbe soaked in water for at least 24 h. Precondition the brush as directed in 7.2.1 before starting the test work.7.3 Brush HolderFor washability testers that include a separate b
30、rush holder, insert a 3.2-mm (18-in.) thick rubber mat in theholder above the brush block. When in operation, this mat allows the brush to ride evenly on the paint surface without tilting. Thebrush must fit loosely in the holder. Mount the brush in the holder being sure that the mat is in place abov
31、e the brush block andthat the brush and holder are always in the same position.TEST METHOD A8. Procedure8.1 Stir the test paint thoroughly and strain to remove all skins and particles. Make three drawdowns of each paint. Draw downthe paint on the black plastic panel using the same operator and same
32、0.18-mm (7.0-mil) clearance film applicator. The time forapplication should be fairly slow 3 to 4 s from end to end to prevent formation of pinholes or holidays in the film. Air dry in ahorizontal position for 7 days in an conditioning chamber at 23 6 2C (73.5 6 3.5F) and 50 6 5 % relative humidity
33、inaccordance with Specification D3924.8.2 Soak the brush in water overnight. Clean the plate and set it in the pan of the washability tester. Ensure that the shim issmooth and free of burrs and placed perpendicular to the path of the brush. Wipe the test panel carefully and place it on top ofthe shi
34、mmed plate with the painted side up. Be sure that there are no defects in the film above the shim and that the test area islevel. Place the frame over the drawdown being sure that the entire gasket is on the painted surface. Clamp the gasket in place.The clamps should be tight enough to ensure close
35、 contact, but not tight enough to cause warping of the panel.8.3 Before beginning the test, it should be confirmed that the brush has been preconditioned for 400 cycles as outlined in 7.2.1.Remove the brush and shake vigorously to remove any excess water. Stir the abrasive scrub medium and spread 10
36、 g uniformlyover the brush bristles. Place the brush at one end of the path. Wet the panel with 5 mL of water in the path of the brush.8.4 Start the test. After each 400 cycles before failure, remove the brush (do not rinse), add 10 g of stirred abrasive scrubmedium and place 5 mL of water on the pa
37、th of the brush before continuing.8.5 Record the number of cycles to remove one continuous thin line of paint film across the 12.7-mm (12-in.) width of the shim.Stop the machine and wipe off the shim area to determine, if necessary, if the end point is achieved.8.6 Test two of the drawdowns. If the
38、two results differ by more than 30 % of the average, test the third drawdown. If one ofthe three results is obviously discrepant, discard it, then average the results from the remaining drawdowns.TEST METHOD B9. Procedure9.1 Stir the test paint and reference paint thoroughly and strain to remove all
39、 skins and particles. Draw down the test andreference paints side by side perpendicular to the length of the panel following procedures outlined in 8.1. Prepare threedrawdowns for each test/reference paint. The paints should be drawn down simultaneously and the painted portion should be inthe middle
40、 of the chart. Air dry in a horizontal position for 7 days at standard conditions.9.2 Soak the brush in water overnight. Clean the plate and set it in the pan of the washability machine. Centrally place twoshims, one each under the test paint and one under the reference paint drawdown areas on the c
41、hart. Wipe the test panel carefullyand place it on top of the shimmed plate with the painted side up. Be sure that there are no defects in the film above the shimsand that the test areas are level. Place the gasket over the painted surface and clamp in place.9.3 Remove the brush and shake it vigorou
42、sly to remove any excess water. Before testing, the brush shall be conditioned for400 cycles as outlined in 7.2.1. Follow procedures outlined in 8.3 and 8.4. It is recommended that the first two panels to be testedare prepared by altering the position of the reference paint, that is, one panel has t
43、he reference paint on the right, and the secondpanel has the reference paint on the left.9.4 Record respectively the number of cycles to remove one continuous thin line of paint film from both the test and referencepaints across the 12.7-mm (12-in.) width of each of the shims. Stop the machine and w
44、ipe off the shim areas to determine, ifnecessary, if each end point is achieved.9.5 Test two of the drawdowns. If the two results differ by more than 30 %, test the third drawdown. If one of the three resultsis obviously discrepant, discard it, then average the results from the remaining drawdowns.D
45、2486 17410. Report10.1 Report the following information:10.1.1 When using Test Method A, report the mean number of cycles to failure.10.1.2 When using Test Method B, report a percentage as follows:Cycles for test paintCycles for reference paint 3100 (1)if:Result is 100 %, test paint has better scrub
46、 resistance than reference paint.if:Result is 100 %, test paint has poorer scrub resistance than reference paint.10.1.3 Method used (Test Method A or Test Method B).10.1.4 Referenced paint used, if using Test Method B.10.1.5 Outline any deviations from standard procedures.11. Precision and Bias11.1
47、PrecisionIn an interlaboratory study of these test methods, scrub resistance was recorded in five laboratories using threecoatings. The following criteria should be used for judging the acceptability of results of scrub resistance tests at a 95 % confidencelevel.Test Method A11.1.1 RepeatabilityDupl
48、icate results by a single operator should be considered suspect if they differ by more than 30 % oftheir mean value.11.1.2 ReproducibilityTwo results (each the mean of duplicate measurements) obtained by operators in different laboratoriesshould be considered suspect if they differ by more than 58 %
49、 of their mean.Test Method B11.1.3 On the basis of an interlaboratory study in which operators in five laboratories tested five coatings, including both flatand semi-gloss coatings, the following criteria should be used for judging the acceptability of the results at the 95 % confidencelevel:11.1.3.1 RepeatabilityTwo results (each the mean of duplicate measurements) obtained by the same operator should beconsidered suspect if they differ by more than 25 % of their mean value.11.1.3.2 ReproducibilityTwo results (each the mean of duplicate measurem
