1、Designation: D1653 13Standard Test Methods forWater Vapor Transmission of Organic Coating Films1This standard is issued under the fixed designation D1653; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 number in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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. Scope*1.1 These test methods cover the determination of the ra
3、te 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 A similar, but more generally applicable test method isTest Methods E96 which should be considered when othermaterials are invo
4、lved.1.3 Two test methods are covered in Test Methods D1653 asfollows:1.3.1 Test Method ADry Cup Method, and1.3.2 Test Method BWet (Payne) Cup Method.1.3.3 Agreement should not be expected between resultsobtained by different methods or test conditions. The methodthat most closely approaches the con
5、ditions of use should beselected.1.4 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard. Factors for conversion arestated in 13.2.1.2 and 13
6、.2.2.2.1.5 There are instruments on the market that purport tomeasure water vapor transmission of films more easily andrapidly than the methods described in Test Methods D1653 andE96. They run essentially the same kinds of tests as in theASTM methods, but do so instrumentally. However, it appearstha
7、t no side-by-side tests have been run comparing results frommeasurements with such instruments to these ASTM methodsfor precision and accuracy.1.6 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 es
8、tablish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsD1005 Test Method for Measureme
9、nt of Dry-Film Thick-ness of Organic Coatings Using MicrometersD1193 Specification for Reagent WaterD4708 Practice for Preparation of Uniform Free Films ofOrganic CoatingsE96 Test Methods for Water Vapor Transmission of Materi-alsE104 Practice for Maintaining Constant Relative Humidityby Means of Aq
10、ueous Solutions3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 water vapor transmission rate, WVT, nthe steadywater vapor flow in unit time through unit area of a body,between two specific parallel surfaces, under specific condi-tions of temperature and humidity at each surfac
11、e. Acceptedinch-pound unit is grains per square foot per hour.Accepted SIunit is grams per square metre per 24 h.3.1.2 water vapor permeance, WVP, nthe steady watervapor flow in unit time through unit area of a body (WVT)induced by unit vapor pressure difference (p) between the twosurfaces of a coat
12、ing. Therefore, WVP = WVT/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 of mercury (called a metricperm).3.1.3 vapor source, nhumidity in the dry cup method andwater in the wet cup m
13、ethod.3.1.4 vapor sink, ndesiccant used in the dry cup methodand 50 % or near 0 % relative humidity in the wet cup method.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 containing1These test methods are under the jurisdi
14、ction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the directresponsibility of Subcommittee D01.23 on Physical Properties of Applied PaintFilms.Current edition approved June 1, 2013. Published July 2013. Originally approvedin 1959. Last previous edition app
15、roved in 2008 as D1653 03 (2008). DOI:10.1520/D1653-13.2For 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.*A Sum
16、mary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1desiccant, and the assembly placed in a test chamber with acontrolled atmosphere. Two sets of exposure conditions areacceptable
17、 for 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 pl
18、aced 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), and4.2.2 Condition C, consisting of very low (near zero)relative humidity at 73F (23C).4.3 In both methods, peri
19、odic 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 services, for
20、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 test methods
21、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 of water vap
22、or 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 relativehumidity, and if their thicknesses are equal.5.5 Test Method AThe Dry Cup Method is the prefe
23、rredtest 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 in the vicinity
24、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 water may make a co
25、atingless 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 vapor. Ifthe cup o
26、r 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 facesof the flanges
27、 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 together withsui
28、table 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 relativehumidity as specified in Section 4. Air shall be circulatedthroughout the chamber to maintain uniform
29、 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 E104.6.3 Analytical Balance, having an adequate capaci
30、ty 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 D1193.7.2 Desiccant, consisting of either anhydrous calcium chlo-ride
31、(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 testmust be limited
32、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 tothe top of the perm
33、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-filled dish.NOTE 1
34、Among 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 Substrate, prepare free films, whenever possibleto eliminate the potential interference of substrates, on re
35、leasepaper3glass coated with halosilane compound, polyhexafluo-ropropylene sheet, or metal panels wrapped with Tedlar43The sole source of supply of release Paper, Form RP-1K, known to thecommittee at this time is the Leneta Co., 15 Whitney Rd., Mahwah, NJ 07430. Ifyou are aware of alternative suppli
36、ers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.4Tedlar is a registered trademark of E. I. du Pont de Nemours and Company orits affiliates.D1653 132polyvi
37、nylfluoride film (useful for coatings that must be baked)following procedures outlined in Practice D4708.7.5 Film Support, for preparing films that are too brittle orotherwise unsatisfactory for handling as free films. Supportmaterials such as paper charts,5filter paper, and glass clothhave been fou
38、nd satisfactory 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 me
39、thods described in Practices D823 or D4708.NOTE 2Special test conditions may require that the coating be appliedby brushing, roller coating or other special methods. The thickness of thecoating applied shall be within normal range for the type of material undertest, and shall not vary by more than 5
40、 % of the total thickness in any testseries.NOTE 3When applying baking finishes, bake for specified time andtemperature in accordance with manufacturers 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 7da
41、ys 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 from the substrate and allow thepreviously unexposed surface to dry for an additional 7 days.The drying schedule may be modified as recommended bymanufa
42、cturer.NOTE 4Examine test films for the presence of pinholes or otherdefects before commencing the test. It may be advisable to apply the testmaterial in two coats, applying the second coat perpendicular to the firstcoat and allowing for an adequate drying period between coats to achievethe desired
43、film thickness.8.3 Measure the thickness of the test specimen in severalplaces with a micrometer using procedures in Test MethodD1005 to ensure a uniform thickness.8.4 When coatings are applied to support materials, thecoated side of the test specimen should be placed away fromthe desiccant or towar
44、ds the water in the cup, depending uponthe service environment. Coatings should not be applied toboth sides of a support. Glass cloth is preferred for coatingsthat are cured by baking.TEST METHOD ADRY CUP METHOD9. Test Conditions9.1 Unless other conditions are agreed upon between thepurchaser and th
45、e 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 (23 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
46、. 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 mm) 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 pos
47、ition.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 carefully 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 ove
48、r 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 support, place the coated side away from thedesiccant in the cup.NOTE 5Imperfections in the film that are not readily visible mayproduce inconsistent r
49、esults; 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 being 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 In general, weigh the cups every 24 h for a period of 3weeks, or until the weight change versus time b
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