1、Designation: D 1653 03Standard Test Methods forWater Vapor Transmission of Organic Coating Films1This standard is issued under the fixed designation D 1653; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、 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 These test methods cover the determination of the
3、rate atwhich water vapor passes through films of paint, varnish,lacquer, and other organic coatings. The films may be free filmsor they may be applied to porous substrates.1.2 Two test methods are covered as follows:1.2.1 Test Method ADry Cup Method, and1.2.2 Test Method BWet Cup Method.1.2.3 Agreem
4、ent should not be expected between resultsobtained by different methods or test conditions. The methodthat most closely approaches the conditions of use should beselected.1.3 The values stated in inch-pound units are to be desig-nated as the standard. Factors for conversion are stated in13.2.1.2 and
5、 13.2.2.2.1.4 This standard does not purport to address the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Do
6、cuments2.1 ASTM Standards:D 823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test Panels2D 1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using Micrometers2D 1193 Specification for Reagent Water3D 4708 Practice for Preparat
7、ion of Free Films of OrganicCoatings2E 104 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Solutions43. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 water vapor transmission rate, WVTthe steady wa-ter vapor flow in unit time through unit area of a body,
8、betweentwo specific parallel surfaces, under specific conditions oftemperature and humidity at each surface. Accepted inch-pound unit is grains per square foot per hour. Accepted SI unitis grams per square metre per 24 h.3.1.2 water vapor permeance, WVPthe steady water va-por flow in unit time throu
9、gh unit area of a body (WVT)induced by unit vapor pressure difference (Dp) between the twosurfaces of a coating. Therefore, WVP = WVT/D p. Acceptedinch-pound unit is grains per square foot per hour per inch ofmercury (called a perm). Accepted SI unit is grams per squaremetre per 24 h per millimetre
10、of mercury (called a metricperm).4. Summary of Test Methods4.1 In Test Method A (Dry Cup Method), the test specimenis sealed to the open mouth of a cup or dish containingdesiccant, and the assembly placed in a test chamber with acontrolled atmosphere. Two sets of exposure conditions areacceptable fo
11、r this test method.4.1.1 Condition A, consisting of 50 % relative humidity at73F (23C), and4.1.2 Condition B, consisting of 90 % relative humidity at100F (38C).4.2 In Test Method B (Wet Cup Method), the test specimenis sealed to the open mouth of a cup or dish containing water,and the assembly place
12、d in a test chamber with a controlledatmosphere. Two sets of exposure conditions are acceptable forthis test method:4.2.1 Condition A, consisting of 50 % relative humidity at73F (23C), and1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, an
13、d Applications and are the directresponsibility of Subcommittee D01.23 on Physical Properties of Applied PaintFilms.Current edition approved July 10, 2003. Published August 2003. Originallyapproved in 1959. Last previous edition approved in 1999 as D 1653 - 99e1.2Annual Book of ASTM Standards, Vol 0
14、6.01.3Annual Book of ASTM Standards, Vol 11.01.4Annual Book of ASTM Standards, Vol 11.03.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2.2 Condition C, consisting of very low (near zero)relative humidity at 73F (23C).4.3 In both
15、methods, periodic weighings of the cup or dishare made to determine the rate of water vapor movementthrough the specimen.5. Significance and Use5.1 One of the factors affecting the performance providedby an organic coating is its capability of resisting or aiding thepassage of water vapor. In some s
16、ervices, for example, exteriorwood and masonry, the coating has to allow moderate amountsof water vapor to pass through the film without damage to it.Hence, the water vapor transmission characteristics of coatingsare important in assessing their performance in practical use.5.2 The purpose of these
17、test methods is to obtain values ofwater vapor transfer through coatings that range in permeabil-ity from high to low. These values are for use in design,manufacture, and marketing.5.3 The water vapor transmission is not a linear function offilm thickness, temperature or relative humidity.5.4 Values
18、 of water vapor transmission rate (WVT) andwater vapor permeance (WVP) can be used in the relativerating of coatings only if the coatings are tested under the sameclosely controlled conditions of temperature and relative hu-midity, and if their thicknesses are equal.5.5 Test Method AThe Dry Cup Meth
19、od is the preferredtest method for obtaining values that relate to conventionaldwellings where high relative humidities are not anticipated.5.6 Test Method BThe Wet Cup Method is the preferredtest method for obtaining values that relate to applicationswhere high relative humidities are anticipated i
20、n the vicinity ofthe barrier material. In general, the more permeable a coatingis to the passage of moisture as is typical of many water-reducible coatings, the greater its affinity for water and thegreater the increase in transmission when tested in and exposedto high humidities. Absorption of wate
21、r may make a coatingless dense, thus allowing moisture to diffuse easily and cause amuch higher moisture vapor transmission rate, (WVTR) thanwould occur in drier environments.6. Apparatus6.1 Perm Cup or Dish, consisting of a container made of anoncorroding material, impermeable to water or water vap
22、or. Ifthe cup or dish is made of aluminum, it must be anodized orgiven a protective clear coating to prevent corrosion.6.1.1 One type of cup that is suitable has a flanged edge andis equipped with a separate corresponding flange, so that thetest specimen can be held between them. The contacting face
23、sof the flanges shall be ground to such flatness that when thefilm is in position, moisture transfer can occur only through theexposed film area. For hard films, or films having a very roughsurface, a soft rubber gasket may be inserted between the filmand the flange. The flanges shall then be held t
24、ogether withsuitable clamps.6.1.2 Another suitable cup is any open circular or rectangu-lar dish to which the test film can be sealed with wax or sealant.6.2 Test Chamber, with a controlled temperature and rela-tive humidity as specified in Section 4. Air shall be circulatedthroughout the chamber to
25、 maintain uniform conditions at alltest locations. For low or high humidity conditions, a standarddesiccator or other suitable cabinet may be used. For maintain-ing constant relative humidity by means of aqueous solutions,refer to procedures outlined in Practice E 104.6.3 Analytical Balance, having
26、an adequate capacity for theweight of the test cups and a sensitivity of 1 mg.7. Reagents and Materials7.1 Purity of WaterUnless otherwise indicated, referenceto water shall be understood to mean reagent water conformingto Type IV of Specification D 1193.7.2 Desiccant, consisting of either anhydrous
27、 calcium chlo-ride (CaCL2) or anhydrous magnesium perchlorate (Mg-(CLO4)2). The calcium chloride should be dried at 400F(200C) before use. If calcium chloride will react with the testspecimen, an adsorbing desiccant such as a silica gel may beused but the moisture gain by this desiccant during the t
28、estmust be limited to 4 %. Use caution in handling magnesiumperchlorate because of possible chemical reaction that may beproduced if it comes in contact with some organic materialsand is subsequently heated to regenerate the anhydrous salt.7.3 Sealant, such as wax for attaching the test specimen tot
29、he top of the perm cup or dish. It must be highly resistant tothe passage of water vapor. It must not lose weight to, or gainweight from, the atmosphere in an amount, over the requiredperiod of time, that would affect the test results by more than2 %. It must not affect the vapor pressure in a water
30、-filled dish.NOTE 1Among acceptable sealants are (1) a 60:40 mixture ofmicrocrystalline wax and refined crystalline parafin wax, ( 2) tissueembedding wax, and (3) a 50:50 mixture of beeswax and rosin.7.4 Release Paper, prepare free films, whenever possible toeliminate the potential interference of s
31、ubstrates, on releasepaper5or glass substrates following procedures outlined inPractice D 4708.7.5 Film Support, for preparing films that are too brittle orotherwise unsatisfactory for handling as free films. Supportmaterials such as paper charts,6filter paper, and glass clothhave been found satisfa
32、ctory in some instances. Such supportcan have an effect on the test results.8. Test Specimens8.1 It is very important that the test specimens be smooth,and completely continuous films of uniform thickness through-out the test area. Apply air drying coatings to substrates usingone of the methods desc
33、ribed in Practices D 823 or D 4708.NOTE 2Special test conditions may require that the coating be appliedby brushing, roller coating or other special methods. The thickness of the5The sole source of supply of release Paper, Form RP-1K, known to thecommittee at this time is the Leneta Co., 15 Whitney
34、Rd., Mahwah, NJ 07430 . Ifyou are aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.6The sole source of supply of paper charts, F
35、orm NWK, known to the committeeat this time is the Leneta Co., 15 Whitney Rd., Mahwah, NJ 07430 . If you are awareof alternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical com
36、mittee,1which you may attend.D1653032coating applied shall be within normal range for the type of material undertest, and shall not vary by more than 5 % of the total thickness in any testseries.NOTE 3When applying baking finishes, bake for specified time andtemperature in accordance with manufactur
37、ers instructions. Permeancemay vary with the baking schedule or the time of air drying.8.2 Air dry the coated material in a horizontal position for 7days in a room preferably maintained at 73.5 6 3.5F (23 62C) and 50 6 5 % relative humidity. If the material is to betested as a free film, remove it f
38、rom the substrate and allow thepreviously unexposed surface to dry for an additional 7 days.The drying schedule may be modified as recommended bymanufacturer.NOTE 4Examine test films for the presence of pinholes or otherdefects before commencing the test. It may be advisable to apply the testmateria
39、l in two coats, applying the second coat perpendicular to the firstcoat and allowing for an adequate drying period between coats to achievethe desired film thickness.8.3 Measure the thickness of the test specimen in severalplaces with a micrometer using procedures in Test MethodD 1005 to ensure a un
40、iform thickness.8.4 When coatings are applied to support materials, thecoated side of the test specimen should be placed away fromthe desiccant or towards the water in the cup, depending uponthe service environment. Coatings should not be applied toboth sides of a support. Glass cloth is preferred f
41、or coatingsthat are cured by baking.TEST METHOD ADRY CUP METHOD9. Test Conditions9.1 Unless other conditions are agreed upon between thepurchaser and the seller, the tests shall be performed under oneor more of the following conditions:9.1.1 Condition ATest chamber or cabinet maintained at73 6 1F (2
42、3 6 0.6C) and 50 6 2 % relative humidity.9.1.2 Condition BTest chamber or desiccator maintainedat 100 6 1F (38 6 0.6C) and 90 6 2 % relative humidity.10. Procedure10.1 Prepare at least three perm cups or dishes for each testmaterial as follows:10.1.1 Fill the cups with desiccant to within14 in. (6 m
43、m) ofthe top edge.10.1.2 If the cups are equipped with flanges, place the testspecimen between the flanges and adjust the clamps to hold itfirmly in position.10.1.3 If the cups are not equipped with flanges, seal the testspecimen to the top edge of the cups with wax as follows:10.1.3.1 First careful
44、ly place the test specimen, cut to thesize of the frame, on a thin cardboard ring soaked in moltenwax.10.1.3.2 Then place the specimen-covered frame over themouth of the cup. Thoroughly seal the frame to the edge of thecup at the temperature to be used in the test. If the coating is ona substrate or
45、 support, place the coated side away from thedesiccant in the cup.NOTE 5Imperfections in the film that are not readily visible mayproduce inconsistent results; consequently make sure that the test isalways run at least in triplicate.10.2 Weigh the loaded cups to 1 mg and if a test chamber isnot bein
46、g used, place them in the test cabinets or desiccators.Record time, temperature, and relative humidity.10.3 Remove if necessary, the cups for periodic weighing todetermine weight gain. Coatings expected to have high WVTratings, over 10 perms, may require weighings more frequentlythan once a day.10.4
47、 In general, weigh the cups every 24 h for a period of 3weeks, or until the weight change versus time becomesconstant. Record the time that weighings are taken to theprecision of approximately 1 % of the time span betweenweighings. Thus, if weighings are made every day, a time to thenearest 15 minut
48、es would be allowed.10.5 Shake cups containing desiccant everyday to preventsurface saturation of the material. If moisture absorbed by thedesiccant exceeds 20 % of the desiccant weight, discontinuethe test.10.6 Return the cups to the test chamber immediately afterweighing.TEST METHOD BWET CUP METHO
49、D11. Test Conditions11.1 Unless other conditions are agreed upon between thepurchaser and the seller, perform the test(s) under one or moreof the following conditions:11.1.1 Condition ATest chamber or cabinet maintained at73 6 1F (23 6 0.6C) and 50 6 2 % relative humidity.11.1.2 Condition CTest chamber or desiccator maintainedat 73 6 1F and very low (near zero) relative humidity.12. Procedure12.1 Prepare at least three cups for each test material asfollows:12.1.1 Fill the cups with water to within14 in. (6 mm) of thetop edge.12.1.2 If the cups are
