1、Designation: D 7377 07Standard Practice forEvaluating the Water Wash-Off Resistance of Traffic Paints1This standard is issued under the fixed designation D 7377; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 A newly applied traffic paint film may be exposed tohard rain shortly after application. This practice was designedto simulate
3、 that condition and covers determination of thewater wash-off resistance of an applied traffic paint film undercontrolled conditions. This test can be used to compareconventional and fast-dry traffic paints and the binders used inthem for their relative ability to withstand heavy rain soon afterappl
4、ication on roadway surfaces.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of th
5、is 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 562 Test Method for Consistency of Paints MeasuringKrebs Unit (KU) Viscosity Using a Stormer-Type Viscom-eterD711 Tes
6、t Method for No-Pick-Up Time of Traffic PaintD 823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsD 1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD 1212 Test Methods for Measurement of Wet Film Th
7、ick-ness of Organic CoatingsD 4414 Practice for Measurement of Wet Film Thickness byNotch Gages3. Terminology3.1 Definitions:3.1.1 conventional waterborne traffc paint, nan aqueoustraffic paint that uses a conventional-dry latex binder. Typicalno-pick-up dry times for conventional traffic paints are
8、 20 to 45min.3.1.2 durable fast-dry waterborne traffc paint, nan aque-ous traffic paint that uses a third generation durable fast-drylatex binder. Air or airless spray application on roadways istypically 0.65 mm (25 mils) wet or about 0.41 mm (16 mils)dry. The range of application for durable waterb
9、orne paints is0.56 to 0.89 mm (22 to 35 mils) wet, but sometimes the durablepaints are also striped at standard line thickness.3.1.3 effective water wash-off dry time, nthe traffic paintdry time required for no visible loss of coating when conduct-ing the water-wash off Standard Practice.3.1.4 fast-
10、dry waterborne traffc paint, nan aqueous trafficpaint that uses a fast-dry traffic latex binder. Typical no-pick-updry times for fast-dry traffic paints are 10 min.3.1.5 standard line fast-dry waterborne traffc paint, nanaqueous traffic paint that uses a first or second generationfast-dry latex bind
11、er. Air or airless spray application onroadways is typically 0.38 mm (15 mils) wet or about .223 mm(9 mils) dry.3.1.6 waterborne traffc paint, nan aqueous traffic paint(usually white or yellow) containing either a conventional orfast-dry latex binder.4. Summary of Practice4.1 This standard practice
12、involves preparing a series ofuniform thickness films of traffic paint on standard substrates.The films are allowed to dry over different time periods, andthen each paint film is subsequently tested with the water-wash-off test to determine the relative amount of coatingremaining at the end of the w
13、ash off period.5. Significance and Use5.1 After waterborne traffic paints are applied to a roadpavement, it is important that they be sufficiently coalesced orcured so they will not be removed by rain. This practice can beused to determine the relative performance of binders and other1This practice
14、is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.44 on Traffic Coatings.Current edition approved July 1, 2007. Published August 2007.2For referenced ASTM standards, visit the ASTM website, ww
15、w.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 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Sponents wi
16、thin traffic paint for their effect on the water-wash off resistance of the coating. Some key elements of thecoating that may affect water-wash-off performance are thequality and type of latex binder, the dry time of the coating(often conducted by Test Method D711), pigment volumeconcentration (PVC)
17、, and the relative water sensitivity ofadditives (for example, pigment dispersants, surfactants) in thecoating.6. Apparatus and Equipment6.1 Paddle Type Viscometer, to measure viscosity (in Krebsunits) of the traffic paint prior to application.6.2 Conditioned Room,at236 2C (73.5 6 3.5F) and 506 5 %
18、relative humidity for film draw-downs and film drying.6.3 Humidity, to record relative humidity during the dryingperiod.6.4 Thermometers, to record the air and water temperatures.6.5 Spatula, to mix the paint prior to application.6.6 Glass Plates, for film draw-downs (see also option forcharts in 6.
19、7).6.7 Draw-Down Chart, preferred option for film draw-downs. Black Scrub Test Panels are preferred and can be cut inhalf to give two test panels of 16.5 by 21.6 cm (612 by 812 in.)size. Use of these charts instead of a glass plate allows for apermanent record of the test results.6.8 Film Applicator
20、 (15 cm (6 in.) width, to obtain 0.38 mm(15 mil) wet thickness for standard traffic paints or 0.64 mm(25 mil) wet thickness for durable traffic paints.6.9 Wet Film Gage, to measure wet film thickness.6.10 Sink with combined hot and cold tap water faucet,toapply water stream to the test panel.6.11 La
21、b Jack, to support the applied paint film, and tocontrol distance from the water nozzle.6.12 Timer, to time the film-drying and the water wash-offperiods.6.13 Camera, to record the image of the panel after comple-tion of the test.7. Reagents7.1 Tap Water (Cold)applied to the film preferably with ast
22、andard nozzle, at controlled flow rate, controlled watertemperature, and constant distance from the test paint films.7.2 Acetoneto clean glass plates prior to application (notneeded for draw-down charts since they are not reused).8. Procedure8.1 Paint Consistency:8.1.1 Determine the Krebs (KU) visco
23、sity of the paint inaccordance with Test Method D 562 using a paddle-typeviscometer as prescribed by Test Method D 562. This determi-nation is optional but can be important since the dry time of thetraffic paint and water-wash off performance can be affected bythe paint viscosity.8.2 Application of
24、Paint Films:8.2.1 Select the appropriate draw-down bar to obtain a 0.38mm (15 mil) wet film thickness for standard traffic paints or a0.64 mm (25 mil) wet film thickness for durable traffic paints.This determination should be made in advance using PracticeD 823 by making a series of draw-downs with
25、differentapplicator gaps and measuring the wet-film thickness of eachusing Test Method D 1212 or Test Method D 4414. The actualwet film thickness is often much lower than the indicated filmapplicator gap, for example, a 25 mil gap may produce a 15 milwet film thickness. Dry film thickness can option
26、ally bedetermined using Test Method D 1005. Clean a series of fourglass plates with acetone, or optionally use the preferred blackdraw-down charts for the film draw-downs. Allow the glassplates or charts to equilibrate to room temperature.Acontrolledtemperature and humidity environment for the draw-
27、downs andpanel drying is recommended. Place about 10 ml of paint onthe top center of the glass plate or draw-down chart and dragthe draw-down bar over the paint to produce a coating ofuniform thickness. Immediately start a timer for each filmdrawn-down, and allow the films to dry undisturbed for the
28、designated time period. Let one film dry for exactly 15 min.,one for 30 min., one for 45 min., and one for 60 min.At the endof each dry time period, the water wash-off test is conducted onthe paint film (see 8.3).8.3 Running Water Wash-Off Test:8.3.1 Select a sink deep enough for the wash-off test w
29、ith aminimum of 40 cm (16 in.) distance from the faucet nozzle tobottom of sink. Turn both the cold and hot water faucets on,and adjust the flow rate and water temperature to 5.7 L/min(1.5 gal/min) and 25C respectively. The flow rate can bedetermined using a graduated cylinder to measure the volumeo
30、ver a fixed period of time. The standard nozzle opening is 1.0cm (0.40 in.). Any deviation from nozzle size, flow rate, orwater temperature will give different results and should berecorded if not standard. A flow regulator to control the waterpressure may be helpful to provide the correct predeterm
31、inedflow rate.8.3.2 Place a lab jack in the sink and adjust the height fromthe platform to the water faucet nozzle to keep the distanceconstant. A distance of 30.5 cm (12 in.) is standard. Thisadjustment is important particularly if different sinks are usedfor the test. The drain should remain unobs
32、tructed so that thesink does not fill with water during the test. After the dry timehas expired and with the water flow/temperature alreadyadjusted, place the glass panel or draw-down chart on the labjack with the flow impinging on the center of the paint film andimmediately start the timer. Watch t
33、he paint film and record thetime it takes for the water to break through the film. Allow thefilm to remain under the flow of water for a full 5 min. and thenremove it. Note any blistering or softening of the remainingpaint film. At the appropriate times, test the remaining filmpanels in similar fash
34、ion. A camera can be used to obtain apicture for a comparative record of the test results. The blacksubstrates are particularly good for contrast of the area washedoff (black substrate will show) with the white or yellow paintfilm remaining. If glass panels are used, they can be placed ona black sub
35、strate for similar contrast. For clean-up of glassplates, run the plates under hot water to loosen the film andthen scrape the paint off with a razor blade scraper. Thedraw-down charts can simply be discarded or retained forvisual record.D73770728.4 Relative Water Wash-Off Performance for a Test Ser
36、ies,see Fig. 1.9. Report9.1 The following ideally should be recorded when usingthis practice:9.1.1 Viscosity of the paint in Krebs Units (KU),9.1.2 Drying conditions (temperature and humidity), wetfilm thickness, and dry times for each draw-down,9.1.3 Water nozzle used, water temperature, distance t
37、opanel, and water flow rate, and9.1.4 Relative water wash-off performance comparisons fora given set of panels, that is, panels can be ranked from best toworst or pictures can be taken as a relative performance record,or both.10. Keywords10.1 rain resistance; traffic paint; water resistance; waterwa
38、sh-off test;ASTM 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 validity of any such patent rights, and the riskof infringement of such
39、 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 withdrawn. Your comments are invited either for revision of this standard or for additi
40、onal 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
41、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 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).FIG. 1 Illustrative Example of Relative Water Wash-Off Performance for a Test SeriesD7377073
