1、Designation: D 3258 04Standard Test Method forPorosity of White or Near White Paint Films by Staining1This standard is issued under the fixed designation D 3258; 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 This test method covers the determination of the poros-ity of a white or near white mineral spirits insoluble paint filmto ind
3、icate the degree to which a subsequent coat will pen-etrate.1.2 The texture of the film can affect cleanup that willinfluence the results of the test. A stain applied to a high-hidingpaint will not lower the reflectance as much as the same stainapplied to a low-hiding paint of equal porosity. These
4、pointsmust be considered in comparing different paints.1.3 The values stated in SI units are 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 therespo
5、nsibility of the user of this 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:E 97 Test Method for Directional Reflectance Factor, 45-deg, 0-deg, of Opaque Specimens by Br
6、oad-Band FilterReflectometry23. Summary of Test Method3.1 The test paint is applied to a nonporous surface, airdried, then measured for reflectance. A special colored pen-etrating medium is applied, the excess removed in a specifiedmanner, and reflectance measured again. The difference be-tween the
7、two readings indicates the degree of porosity; thesmaller the difference, the lower the porosity of the film and thegreater its ability to resist penetration.4. Apparatus and Materials4.1 Film Applicator, 150 mm (6 in.) wide with a clearanceof 300 m (12 mils).4.2 Film Applicator, 140 mm (512 in.) wi
8、de with a clearanceof 250 m (10 mils).4.3 Reflectometer, meeting the requirements of Test MethodE 97.4.4 Vacuum Drawdown Plate.4.5 Camelhair Brush (approximately 13 mm (12 in.) wide).4.6 Plastic Wash Bottle, containing odorless mineral spirits(about 500 mL (16 oz).4.7 Test PanelSmooth nonporous pane
9、l such as sealedwhite, cardboard chart, or white plastic sheet.4.8 Penetrating MediumA composition of pigment anddark-colored dye dispersed in organic liquid vehicle.4.9 Filter Paper.5. Procedure5.1 Place the test panel on the vacuum plate and apply thepaint under test with the 30-m (12-mil) clearan
10、ce drawdownblade. Remove the test panel from the vacuum plate and air dry48 h under standard conditions of 23 6 2C (73 6 3.5F) and50 6 5 % relative humidity.5.2 Determine the percent reflectance of the dry film usingthe green filter on the reflectometer. When making this reading,back up the panel wi
11、th a flat rigid opaque object and mark thearea on which the reading was made.5.3 Place the panel containing the dry paint film on thevacuum plate. Using the 25-m (10-mil) clearance blade, applythe penetrating medium over the test paint, covering the areamarked as above and drawing the applicator bla
12、de in the samedirection as before.5.4 After 5 min 6 15 s wash off excess penetrating medium.To do this, hold the panel vertically and remove the mediumusing the camelhair brush wet with odorless mineral spirits.Repeat the process until most of the excess is removed. Thencontinue to remove more of th
13、e excess by applying mineralspirits directly from the wash bottle to the area above the stainso that it flows across the stained area. Pause to observe thebead that forms at the bottom of the panel. If the bead is notclear, continue washing with mineral spirits until the bead isessentially clear. Te
14、st with filter paper to be sure no dyeremains in the bead.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.42 on Architectural Coatings.Current edition approved June 1, 2004
15、. Published July 2004. Originally approvedin 1973. Last previous edition approved in 2000 as D 3258 00.2Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.5 Hang the panel in a vertical position and air dry for 3 h.As before
16、, read the percent reflectance over the same area ofthe panel with the same flat rigid opaque object behind thepanel.6. Report6.1 Report the difference between the percent reflectance ofthe untested film and that of the penetrated film.7. Precision7.1 On the basis of an interlaboratory study of this
17、 testmethod in which one operator in each of ten laboratories testedpaint films of two nominally different levels of porosity, thewithin-laboratory and between-laboratories standard devia-tions were found to be:Nominal Differencein Reflectance, %Standard DeviationsWithin-Laboratory Between-Laborator
18、ies7 0.27 1.2635 0.60 4.22Based on these standard deviations the following criteriashould be used to judge the precision or results at the 95 %confidence level:7.1.1 RepeatabilityDuplicate results, obtained by a singleoperator, should be considered suspect if they differ by morethan 0.8 % relative f
19、or difference in reflectance levels of about7 % and more than 1.8 % relative for difference in reflectancelevels of about 35 %.7.1.2 ReproducibilityTwo results, each the mean of dupli-cate measurements obtained in different laboratories should beconsidered suspect if they differ by more than 4.0 % r
20、elativefor difference in reflectance levels of about 7 % and 14 %relative for difference in reflectance levels of about 35 %.8. Keywords8.1 film porosity; porosity; resistancepenetration (intopaint films)ASTM International takes no position respecting the validity of any patent rights asserted in co
21、nnection 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 rights, are entirely their own responsibility.This standard is subject to revision at any time by the respo
22、nsible 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 addressed to ASTM International Headquarters. Your comments will receive careful
23、 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,
24、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).D3258042
