1、Designation: D 7377 08Standard 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 Anewly applied traffic paint film may be exposed to rainof varying intensities shortly after application. This practicewas des
3、igned to determine the relative water wash-off resis-tance of an applied traffic paint film under controlled condi-tions. This test can be used to compare conventional andfast-dry traffic paints and the binders used in them for theirrelative ability to withstand rain soon after application onroadway
4、 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 this standard to est
5、ablish 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 Test Method for No-Pi
6、ck-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 Thick-ness of Organi
7、c 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.3.1.1.1 DiscussionTypical no-pick-up dry times for con-ventional traffic paints ar
8、e 20 to 45 min.3.1.2 durable fast-dry waterborne traffc paint, nan aque-ous traffic paint that uses a third generation durable fast-drylatex binder.3.1.2.1 DiscussionAir or airless spray application onroadways is typically 0.65 mm (25 mils) wet or about 0.41 mm(16 mils) dry. The range of application
9、 for durable waterbornepaints is 0.56 to 0.89 mm (22 to 35 mils) wet, but sometimesthe durable paints 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 P
10、ractice.3.1.4 fast-dry waterborne traffc paint, nan aqueous trafficpaint that uses a fast-dry traffic latex binder.3.1.4.1 DiscussionTypical no-pick-up dry 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
11、 second generationfast-dry latex binder.3.1.5.1 DiscussionAir 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 bi
12、nder.4. Summary of Practice4.1 This standard practice 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 r
13、elative amount of coatingremaining at the end of the wash 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 re
14、lative performance of binders and othercomponents within traffic paint for their effect on the water-wash off resistance of the coating. Some key elements of the1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct
15、responsibility ofSubcommittee D01.44 on Traffic Coatings.Current edition approved Feb. 1, 2008. Published March 2008. Originallyapproved in 2007. Last previous edition approved in 2007 as D 7377 - 07.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Servic
16、e 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 States.coating that may affect water-wash-off perform
17、ance are thequality and type of latex binder, the dry time of the coating(often conducted by Test Method D711), pigment volumeconcentration (PVC), and the relative water sensitivity ofadditives (for example, pigment dispersants, surfactants) in thecoating.6. Apparatus and Equipment6.1 Paddle Type Vi
18、scometer, 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 % relative humidity for film draw-downs and film drying.6.3 Humidity Gauge, to record relative humidity during thedrying period.6.4 Thermometers, to record t
19、he 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 6.7).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
20、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 (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 paint
21、s.6.9 Wet Film Gauge, to measure wet film thickness.6.10 Sink with combined hot and cold tap water faucet,toapply water stream to the test panel for the running watermethod.6.11 Water Sprayer (hand pumped type spray bottle oradjustable nozzle garden-type sprayer), to provide a waterspray to the test
22、 panel for the alternative water spray method.6.12 Lab Jack, to support the applied paint film, and tocontrol distance from the water nozzle.6.13 Timer, to time the film-drying and the water wash-offperiods.6.14 Camera, to record the image of the panel after comple-tion of the test.7. Reagents7.1 Ta
23、p Water (Cold)applied to the film preferably with astandard 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 P
24、aint Consistency:8.1.1 Determine the Krebs (KU) viscosity 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
25、be affected bythe paint viscosity.8.2 Application of 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
26、 PracticeD 823 by making a series of draw-downs with 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
27、 milwet film thickness. Dry film thickness can optionally 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.Acontrol
28、ledtemperature and humidity environment for the draw-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
29、-down, and allow the films to dry undisturbed for thedesignated 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 and 8.5).8.3 Running Water Wash-Off
30、 Test:8.3.1 Select a sink deep enough for the wash-off test with 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 b
31、edetermined using a graduated cylinder to measure the volumeover 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
32、waterpressure may be helpful to provide the correct predeterminedflow 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 differ
33、ent sinks are usedfor the test. The drain should remain unobstructed 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 cen
34、ter of the paint film andimmediately start the timer. Watch the 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 app
35、ropriate times, test the remaining filmpanels in similar fashion. 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 remainin
36、g. If glass panels are used, they can be placed ona black substrate for similar contrast. For clean-up of glassplates, run the plates under hot water to loosen the film andD7377082then scrape the paint off with a razor blade scraper. Thedraw-down charts can simply be discarded or retained forvisual
37、record.8.4 Relative Running Water Wash-Off Performance for aTest Series, see Fig. 1.8.5 Alternative Water Spray Wash-Off TestThis waterspray procedure provides an alternative wash-off test withlower water flow rate (0.1 litre/min) than the running waterprocedure (5.7 litre/min.) detailed in 8.3. Usi
38、ng a spray devicethat is capable of delivering an atomized water mist, such as ahand pumped spray bottle or an adjustable nozzle garden-typesprayer, adjust the water flow rate to 0.1 6 0.05 litres per min.On a blank (uncoated) test panel, position and adjust the waterspray with the nozzle such that
39、it provides a uniform spraycovering the width of the wet film. Typically, the spray area isapproximately a 12 6 2 cm circle and the spray nozzle is 15 62 cm from the panel.After the dry time interval has expired andwith the water flow rate adjusted, hold the (coated) test panelvertically and spray w
40、ith water for 10 seconds. The film isconsidered washout resistant when no paint is visibly washeddown from the test area. Alternatively, washout failure can berated by the amount of paint washed down from the test area.Black substrates such as vinyl draw-down charts are particu-larly useful for seei
41、ng and rating wash-off failure.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 Wash-off procedure (running wate
42、r or water spray),water nozzle or spray device used, water temperature, distanceto panel, and water flow rate, and9.1.4 Running water procedure: Relative water wash-offperformance comparisons for a given set of panels, that is,panels can be ranked from best to worst or pictures can betaken as a rela
43、tive performance record, or both.9.1.5 Water spray procedure: Drying time to no paintwash-off.10. Keywords10.1 rain resistance; traffic paint; water resistance; waterwash-off testFIG. 1 Illustrative Example of Relative Running Water Wash-Off Performance for a Test SeriesD7377083ASTM International ta
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