1、Designation: D 2247 02Standard Practice forTesting Water Resistance of Coatings in 100 % RelativeHumidity1This standard is issued under the fixed designation D 2247; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses 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 This practice covers the basic principles
3、 and operatingprocedures for testing water resistance of coatings by exposingcoated specimens in an atmosphere maintained at 100 %relative humidity so that condensation forms on the testspecimens.1.2 This practice is limited to the methods of obtaining,measuring, and controlling the conditions and p
4、rocedures oftests conducted in 100 % relative humidity. It does not specifyspecimen preparation, specific test conditions, or evaluation ofresults.NOTE 1Alternative practices for testing the water resistance ofcoatings include Practices D 870, D 1735, and D 4585.1.3 The values stated in SI units are
5、 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 theresponsibility of the user of this standard to establish appro-priate safety and health practices
6、 and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Varnish, Conversion Coatings, andRelated Coating Products2D 610 Test Method for Evaluating Degree of Rusting
7、 onPainted Steel Surfaces3D 714 Test Method for Evaluating Degree of Blistering ofPaints2D 823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test Panels2D 870 Practice for Testing Water Resistance of CoatingsUsing Water Immersion2D 1193 Specification fo
8、r Reagent Water4D 1654 Test Method for Evaluation of Painted or CoatedSpecimens Subjected to Corrosive Environment2D 1730 Practices for Preparation of Aluminum andAluminum-Alloy Surfaces for Painting5D 1735 Practice for Testing Water Resistance of CoatingsUsing Water Fog Apparatus2D 2616 Test Method
9、 for Evaluation of Visual Color Differ-ence With a Gray Scale2D 3359 Test Methods for Measuring Adhesion by TapeTest2D 3363 Test Method for Film Hardness by Pencil Test2D 4541 Test Method for Pull-Off Strength of CoatingsUsing Portable Adhesion Testers3D 4585 Practice for Testing Water Resistance of
10、 CoatingsUsing Controlled Condensation23. Summary of Practice3.1 Coated specimens are placed in an enclosed chambercontaining a heated, saturated mixture of air and water vapor.The temperature of the chamber is usually maintained at 38C(100F). At 100 % relative humidity (RH), a very smalltemperature
11、 difference between the specimen and the surround-ing vapor causes the formation of condensation on the speci-mens. The exposure condition is varied by selecting theduration of the test. Water permeates the coating at rates thatare dependent upon the characteristics of the coating. Anyeffects such a
12、s color change, blistering, loss of adhesion,softening, or embrittlement are observed and reported.4. Significance and Use4.1 Water can cause the degradation of coatings, so knowl-edge of how a coating resists water is helpful in predicting itsservice life. Failure in tests at 100 % relative humidit
13、y may becaused by a number of factors including a deficiency in thecoating itself, contamination of the substrate, or inadequatesurface preparation. This practice is therefore useful for evalu-ating coatings alone or complete coating systems.1This practice is under the jurisdiction of ASTM Committee
14、 D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.27 on Accelerated Testing.Current edition approved Aug. 10, 2002. Published October 2002. Originallypublished as D 2247 66 T. Last previous edition D 2247 99.2Annual Book of ASTM Standa
15、rds, Vol 06.01.3Annual Book of ASTM Standards, Vol 06.02.4Annual Book of ASTM Standards, Vol 11.01.5Annual Book of ASTM Standards, Vol 02.05.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 Tests at 100 % relative humidity are use
16、d for specifica-tion acceptance, quality control, and research and developmentof coatings and substrate treatments. These tests usually resultin a pass or fail determination, but the degree of failure mayalso be measured. A coating system is considered to pass ifthere is no evidence of water-related
17、 failure after a period oftime.4.3 Results obtained from the use of 100 % humidity tests inaccordance with this practice should not be represented asbeing equivalent to a period of exposure to water in the naturalenvironment, until the degree of quantitative correlation hasbeen established for the c
18、oating or coating system.4.4 The test chamber can be a small laboratory cabinet or aroom large enough to hold an automobile or a truck. Someautomobile manufacturers test completed vehicles in roomsmaintained at 100 % relative humidity. Corrosion tests can beconducted, as the condensate dripping off
19、the test articles is notrecirculated.5. Apparatus5.1 Test Chamber, constructed of corrosion-resistant mate-rials with supports for the test specimens.5.2 Heated Water Tank, within the test chamber, a watersupply, and a water level control.5.3 Thermostatic Control, for the water heater with thesensor
20、 located adjacent to the specimen holders.5.4 Thermometer, with sensor located adjacent to the speci-men holders.5.5 Diagrams and details of the apparatus are shown in theAnnex.6. Test Specimens6.1 This practice does not cover the preparation of testspecimens. The substrate composition and surface p
21、reparation,specimen preparation, and the number of specimens should beagreed upon prior to testing.NOTE 2Applicable methods for the preparation of test panels andsubstrates are given in Practices D 609 and D 1730. Practices D 823 coverapplication techniques for the production of uniform films.6.2 It
22、s recommended that a control specimen of a paintwith known durability be included with each test. Such controlspecimens can provide warning of changes in test severity in agiven apparatus, and can indicate variations in test severitybetween different apparatuses.6.3 Its recommended that at least two
23、 replicate specimensof each different coating be used, so as to compensate forvariations between specimens and variations in test conditionswith the apparatus.7. Procedure7.1 Fill the water tank with reagent water conforming toType IV of Specification D 1193. Tap water should not be used.7.2 Adjust
24、the temperature of the saturated air and watervapor mixture to 38 6 2C (100 6 4F).NOTE 3Due to heat loss to the specimens and the walls of thechamber, the temperature of the water in the tank will be above thetemperature of the air and water vapor mixture.7.3 Support the specimens approximately 15 f
25、rom thevertical. Slotted wood supports are suitable for flat specimens.Provide for formation of condensation on the specimens byspacing them at least 30 mm apart. Space the specimens sothey do not touch each other, any metallic material, or anymaterial capable of acting as a wick. Arrange specimens
26、so thatcondensate from one specimen cannot drip on other specimens.7.4 Droplets of condensation should appear evenly on thespecimen at all times if the chamber is operating properly. Thechamber should be mapped throughout the exposure zone toavoid areas where condensation does not occur on the panel
27、sand reduce variability in the test. Operate the test continuouslywith the test chamber closed unless otherwise specified. Shortinterruptions to inspect or remove specimens are permitted, butsuch interruptions should occur no more than once each day.7.5 To control for variability within the apparatu
28、s, reposi-tion the specimens on a regular basis so that all specimensspend equivalent amounts of time in the various areas of theapparatus (front, back, left, right, and center).7.6 Conclude the test after a specified period of time or aftereffects from exposure to water are observed.7.7 Wipe the te
29、st specimens dry. Rate specimens forchanges in color, blistering, etc. Evaluate specimens no lessthan 5 min and no more than 10 min after removal from test,as the effects from water exposure can change within a shorttime. Remove only as many specimens as can be rated withinthe specified time.NOTE 4
30、Relevant procedures for evaluating water effects are de-scribed in Test Methods D 610, D 714, D 1654, D 2616, D 3359, D 3363,and D 4541.7.7.1 If possible, rate the specimens again after they havebeen removed from the test for a recovery period long enoughthat moisture absorbed within the specimens d
31、ries out and thespecimens reach moisture equilibrium with room air. A recov-ery period from 12 to 24 h is generally sufficient. Thepost-recovery rating allows evaluation of the permanent effectsof the exposure as distinct from the transient effects, and isespecially important for evaluation of color
32、 and gloss.8. Report8.1 Report the following information:8.1.1 Sample identification.8.1.2 Results of the evaluation(s).8.1.3 Reference to Practice D 2247.8.1.4 Hours of test duration.8.1.5 Test temperature.8.1.6 Special conditions of test or any deviations in testprocedure.9. Keywords9.1 adhesion;
33、blistering; humidity; resistance-water; rustD2247022ANNEX(Mandatory Information)A1. ApparatusA1.1 The apparatus must be constructed so that heatedwater vapor is generated at the bottom of the chamber. Thissaturates the air immediately above the water tank with watervapor. The saturated mixture of wa
34、ter vapor and air tempera-ture rises and then cools below the dew point, causingcondensation on the specimens. Two types of apparatus havebeen found to meet the requirements of this practice. One typeuses a water tank with an electric immersion heater, and theother uses a submerged air distribution
35、pipe.A1.2 In chambers using a water tank with electric immer-sion heater to supply heat and humidity, the area of the heatedwater tank should be limited to no more than 25 % of the floorarea of the chamber. The use of a large heated water tank wouldtend to make the temperature within the chamber uni
36、form, andthus inhibit or prevent the formation of condensate on thespecimens. The water temperature will be approximately from5 to 10C (10 to 20F) above the vapor temperature when thewater tank and chamber are properly proportioned.A1.3 In chambers using a water jacket to supply heat andhumidifying
37、tower (optional) and submerged air distributionpipe to supply humidity, the water level in the chamber shouldbe approximately 15 cm (6 in.) above the bottom of thechamber. The level of water in the heating jacket should beapproximately 30 cm (12 in.) above the bottom of the chamber.Samples must be p
38、laced at a level above the water in theheating jacket to insure proper condensation. Air pressure tothe humidifying tower should be approximately 7 to 14 kPa (1to 2 psi).A1.4 Insulation of the enclosure is not required and canpossibly interfere with the formation of condensate by reducingthe tempera
39、ture differential within the chamber. It is difficult toproduce condensation with small chambers because the tem-perature differential is slight.A1.5 Large walk-in chambers may require more than oneheated water tank to generate the convective currents needed tocause condensation at all points within
40、 the chamber. Circulat-ing fans should be used with caution as their use may reducethe temperature differential and limit condensation.A1.6 In a properly operating chamber, condensation isobserved on the specimens or parts when the chamber isopened for inspections. It may be necessary to avoid placi
41、ngspecimens in the lower portion of the chamber as the tempera-ture differentials at the lower levels may be too small to inducecondensation.A1.7 In the event that enough condensation does not occur,or condensation does not form at all the desired points, it ispossible to increase condensation by tu
42、rning off the waterheater periodically to cause temperature fluctuations.A1.8 Many variations in the design of the apparatus arepossible in the use of this practice. Two typical designs areshown in Fig. A1.1 and Fig. A1.2, and Fig. A1.3.D22470230Angle of lid, 90 to 1251Hinged top, hydraulically oper
43、ated, or counterbalanced2Water seal3Constant-level water tank unheated with overflow outlet and equalizerconnection4Heater water tank for supplying heat and humidity to cabinet5Immersion heater6Water temperature limit control7Thermostatic controller for room temperature. Primary limit control forimm
44、ersion heater (5)8Water line9Insulation if necessary (see A1.3)10Temperature recorder (optional)11DrainFIG. A1.1 Humidity Cabinet1Temperature recorder2Fiberglass door with magnetic closers and rubber seal; inward sloping sill3Light switch4Thermostatic controller for room temperature. Primary limit c
45、ontrol forimmersion heater (6)5Heated water tank for supplying heat and humidity to room6Immersion heater7Water temperature limit control8Constant level water tank unheated with overflow outlet9Equalizer connection10Floor drainNOTE 1The chamber shall feature waterproof construction withinsulation an
46、d vaporproof fixtures on the interior, lighting may beaccomplished with a fluorescent fixture above insulating glass sealed inthe ceiling. Polyvinyl chloride pipe and flanges shall be used for sleevesthrough walls.FIG. A1.2 Walk-in Humidity ChamberD2247024FIG. A1.3 Humidity CabinetASTM International
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48、n 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 additional standardsand should be ad
49、dressed 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, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contac
