1、Designation: D 2486 06Standard Test Methods forScrub Resistance of Wall Paints1This standard is issued under the fixed designation D 2486; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in paren
2、theses 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 These test methods cover a procedure for determiningthe resistance o
3、f wall paints to erosion caused by scrubbing,referred to herein after as “scrub resistance.”1.2 Two test methods are covered as follows:1.2.1 Test Method ACycles-to-failure obtained on testpaint.1.2.2 Test Method BRatio expressed as a percentage ofcycles-to-failure obtained on the test paint to that
4、 obtained ona concurrent run with a known reference paint.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is there
5、sponsibility 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.2. Referenced Documents2.1 ASTM Standards:2D 3924 Specification for Environment for Conditioning andTesting Paint, Varnish, Lacquer,
6、 and Related MaterialsD 4213 Test Method for Scrub Resistance of Paints byAbrasion Weight Loss3. Summary of Test Method3.1 In Test Method A, the test paint is applied to a blackplastic panel. After curing, the coated panel is placed over a12.7 wide by 0.25-mm thick (12-in. by 10-mil) shim and heldin
7、 place on a drawdown plate in a washability machine bymeans of a gasketed frame. The coated panel is then scrubbedwith a bristle brush and an abrasive scrub medium until thepaint film is removed in one continuous thin line across theshim.3.2 In Test Method B, the test paint and a reference paint are
8、applied simultaneously perpendicular to the length of the blackplastic panel. After curing, the coated panel is placed over two12.7 by 0.25-mm (12-in. by 10-ml) shims that are positionedunder each coating. The coatings are then scrubbed with abristle brush and an abrasive scrub medium until each pai
9、ntfilm is removed in one continuous thin line across its ownshim.4. Significance and Use4.1 Paints often become soiled, especially near doorways,windows, and in work and play areas. These test methods coverthe determination of the relative resistance of different paints toerosion when repeatedly scr
10、ubbed during the life of the paint.4.2 Test Method D 4213 is a similar scrub resistance testusing a weight-loss technique and reporting volumetric filmerosion rates.4.3 Test Method A measures scrub resistance by the tradi-tional cycles-to-failure concept. Poor correlation in scrubtesting can be attr
11、ibutable to among other things variations inthe stiffness of the brush bristles, condition of washabilitytester, application and drying conditions. In an attempt toimprove reproducibility, Test Method B has been developed.5. Apparatus5.1 Straight Line Washability Machine.5.1.1 Accessory Apparatus: (
12、see Figs. 1 and 2).5.1.1.1 Nylon Bristle Brush and Accessories,(total weight454 6 10 g).5.1.1.2 Drawdown Plate, 454 by 165 by 6.3 mm (1778 by612 by14 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.1These test methods are und
13、er the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility of Subcommittee D01.42 on Architectural Coatings.Current edition approved April 1, 2006. Published April 2006. Originallyapproved in 1966. Last previous edition approv
14、ed in 2000 as D 2486 00.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Ba
15、rr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Film Applicator, having 0.18-mm (7-mil) clearance and6.25-mm (14-in.) edge and width of 135 mm (514-in.).6. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.6.2 Black Plasti
16、c Panels.3,46.3 Abrasive Scrub Medium.4,56.3.1 Laboratory standardized abrasive scrub medium con-sisting of the following:gramsWater, distilled or deionized 49.4AHydroxyethyl cellulose4,60.8Ammonium hydroxide, 28 % 0.1Detergent4,72.0Trisodium phosphate, anhydrous 2.0Silica4,845.0Acetic acid (glacial
17、) 0.7BPreservative4,90.1_AAdjust to achieve viscosity of 110 to 120 Krebs units before use.BVary to achieve a pH of 9.5 to 10.6.4 Reference paint when using Test Method B.7. Preparation of Apparatus7.1 Washability MachineThe straight line washabilitymachine should be leveled before use and operated
18、at 37 6 1cycles per minute.3Dull black plastic panels, P-121-10N, 165 by 432 by 0.25 mm (612 by 17 in.by 10 mils) manufactured by the Leneta Co., 15 Whitney Rd., Mahwah, NJ 07430were used in the original development of this standard in order to get the results inthese test methods.4If you are aware
19、of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.5The sole source of supply of the abrasive scrub medium known to thecommittee at th
20、is time is the Leneta Company.6The sole source of supply of cello size OP-4400, viscosity grade of HEC,known to the committee at this time is Union Carbide, Polymer Division, 318-24Fourth Ave., So. Charleston, WV 25303.7The sole source of supply of the Triton X-100 detergent known to thecommittee at
21、 this time is Union Carbide, 10235 W. Little York Road, Suite 300,Houston, TX 77040.8The sole source of supply of the Tamsil 45, known to the committee at this timeis Unimin Specialty Minerals Inc., 258 Elm St., New Canaan, CT 06840.9The sole source of supply of the 1.3.5-triethyl hexahydro-sym-tria
22、zine (VancideTH), known to the committee at this time is R. T. Vanderbilt Co., 30 Winfield St.,Norwalk, CT 06855.FIG. 1 Accessory Apparatus for Scrub TestFIG. 2 Accessory Apparatus for Scrub TestD24860627.2 BrushReplace the brush when the bristles have be-come worn to a point that the bristles exten
23、d less than 15 mm(58 in.) from the block. Mark the ends of the brush to ensure itis oriented in the same direction for each use.7.2.1 Brushes (that are in frequent use)Brushes that are infrequent use shall be stored in water. Each time before startingthe first test of the day, remove the brush and r
24、inse in water,then precondition the brush, by running it for 400 cycles on ascrub panel, after which it is ready for test work.7.2.2 Brushes (that are not in regular use)Brushes thatwill not be used on a regular basis shall be washed outthoroughly in water after their last use and stored with thebri
25、stling side up under ambient conditions. Before being usedagain, the brush should be soaked in water for at least 24 h.Precondition the brush as directed in 7.2.1 before starting thetest work.7.3 Brush HolderFor washability testers that include aseparate brush holder, insert a 3.2-mm (18-in.) thick
26、rubber matin the holder above the brush block. When in operation, thismat allows the brush to ride evenly on the paint surface withouttilting. The brush must fit loosely in the holder. Mount thebrush in the holder being sure that the mat is in place above thebrush block and that the brush and holder
27、 are always in thesame position.TEST METHOD A8. Procedure8.1 Stir the test paint thoroughly and strain to remove allskins and particles. Make three drawdowns of each paint. Drawdown the paint on the black plastic panel using the sameoperator and same 0.18-mm (7.0-mil) clearance film applicator.The t
28、ime for application should be fairly slow 3 to 4 s fromend to end to prevent formation of pinholes or holidays in thefilm. Air dry in a horizontal position for 7 days in anconditioning chamber at 23 6 2C (73.5 6 3.5F) and 50 65 % relative humidity in accordance with SpecificationD 3924.8.2 Soak the
29、brush in water overnight. Clean the plate andset it in the pan of the washability tester. Ensure that the shimis smooth and free of burrs and placed perpendicular to the pathof the brush. Wipe the test panel carefully and place it on topof the shimmed plate with the painted side up. Be sure thatther
30、e are no defects in the film above the shim and that the testarea is level. Place the frame over the drawdown being surethat the entire gasket is on the painted surface. Clamp thegasket in place. The clamps should be tight enough to ensureclose contact, but not tight enough to cause warping of thepa
31、nel.8.3 Before beginning the test, it should be confirmed that thebrush has been preconditioned for 400 cycles as outlined in7.2.1. Remove the brush and shake vigorously to remove anyexcess water. Stir the abrasive scrub medium and spread 10 guniformly over the brush bristles. Place the brush at one
32、 end ofthe path. Wet the panel with 5 mL of water in the path of thebrush.8.4 Start the test. After each 400 cycles before failure,remove the brush (do not rinse), add 10 g of stirred abrasivescrub medium and place 5 mL of water on the path of the brushbefore continuing.8.5 Record the number of cycl
33、es to remove one continuousthin line of paint film across the 12.7-mm (12-in.) width of theshim. Stop the machine and wipe off the shim area todetermine, if necessary, if the end point is achieved.8.6 Test two of the drawdowns. If the two results differ bymore than 30 % of the average, test the thir
34、d drawdown. If oneof the three results is obviously discrepant, discard it, thenaverage the results from the remaining drawdowns.TEST METHOD B9. Procedure9.1 Stir the test paint and reference paint thoroughly andstrain to remove all skins and particles. Draw down the test andreference paints side by
35、 side perpendicular to the length of thepanel following procedures outlined in 8.1. Prepare threedrawdowns for each test/reference paint. The paints should bedrawn down simultaneously and the painted portion should bein the middle of the chart. Air dry in a horizontal position for7 days at standard
36、conditions.9.2 Soak the brush in water overnight. Clean the plate andset it in the pan of the washability machine. Centrally place twoshims, one each under the test paint and one under thereference paint drawdown areas on the chart. Wipe the testpanel carefully and place it on top of the shimmed pla
37、te withthe painted side up. Be sure that there are no defects in the filmabove the shims and that the test areas are level. Place thegasket over the painted surface and clamp in place.9.3 Remove the brush and shake it vigorously to removeany excess water. Before testing, the brush shall be condition
38、edfor 400 cycles as outlined in 7.2.1. Follow procedures outlinedin 8.3 and 8.4. It is recommended that the first two panels to betested are prepared by altering the position of the referencepaint, that is, one panel has the reference paint on the right, andthe second panel has the reference paint o
39、n the left.9.4 Record respectively the number of cycles to remove onecontinuous thin line of paint film from both the test andreference paints across the 12.7-mm (12-in.) width of each ofthe shims. Stop the machine and wipe off the shim areas todetermine, if necessary, if each end point is achieved.
40、9.5 Test two of the drawdowns. If the two results differ bymore than 30 %, test the third drawdown. If one of the threeresults is obviously discrepant, discard it, then average theresults from the remaining drawdowns.10. Report10.1 Report the following information:10.1.1 When using Test Method A, re
41、port the mean numberof cycles to failure.10.1.2 When using Test Method B, report a percentage asfollows:Cycles for test paintCycles for reference paint3100 (1)if:D2486063Result is 100 %, test paint has better scrub resistance thanreference paint.if:Result is 100 %, test paint has poorer scrub resist
42、ance thanreference 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 PrecisionIn an interlaboratory study of these testmethods, scrub resistance was recorded
43、 in five laboratoriesusing three coatings. The following criteria should be used forjudging the acceptability of results of scrub resistance tests ata 95 % confidence level.Test Method A11.1.1 RepeatabilityDuplicate results by a single operatorshould be considered suspect if they differ by more than
44、 30 %of their mean value.11.1.2 ReproducibilityTwo results (each the mean ofduplicate measurements) obtained by operators in differentlaboratories should be considered suspect if they differ by morethan 58 % of their mean.Test Method B11.1.3 On the basis of an interlaboratory study in whichoperators
45、 in five laboratories tested five coatings, includingboth flat and semi-gloss coatings, the following criteria shouldbe used for judging the acceptability of the results at the 95 %confidence level:11.1.3.1 RepeatabilityTwo results (each the mean of du-plicate measurements) obtained by the same oper
46、ator should beconsidered suspect if they differ by more than 25 % of theirmean value.11.1.3.2 ReproducibilityTwo results (each the mean ofduplicate measurements) obtained by operators in differentlaboratories should be considered suspect if they differ by morethan 58 % of their mean.11.2 BiasBias is
47、 not applicable to these test methods.12. Keywords12.1 scrub resistance; wet abrasion resistanceASTM 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 determin
48、ation 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 years andif not revised, either reapproved or wit
49、hdrawn. 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 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 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
