1、Designation:D325804(Reapproved 2019)Standard Test Method forPorosity of White or Near White Paint Films by Staining1This standard is issued under the fixed designation D3258;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of
2、 last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()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
3、 indicate 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.Astain 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 theresponsi
5、bility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization
6、established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2E1347 Test Method for Color and Color-Difference Mea-surement
7、by Tristimulus Colorimetry3.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 two readin
8、gs 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(512in.)wide with a clearanceof
9、 250 m(10 mils).4.3 Reflectometer,meeting the requirements of Test MethodE1347.4.4 Vacuum Drawdown Plate.4.5 Camelhair Brush(approximately 13 mm(12in.)wide).4.6 Plastic Wash Bottle,containing odorless mineral spirits(about 500 mL(16 oz).4.7 Test PanelSmooth,nonporous panel such as sealedwhite,cardbo
10、ard 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)clearance drawdownblade.Remove the test
11、panel from the vacuum plate and air dry48 h under standard conditions of 23 6 2 C(73 6 3.5 F)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 with a flat,rigid,opaque object and mar
12、k 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 blade in the samedirection as before.5.4 Afte
13、r 5 min 6 15 s,wash off excess penetratingmedium.To do this,hold the panel vertically and remove the1This 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 Coatin
14、gs.Current edition approved April 1,2019.Published April 2019.Originallyapproved in 1973.Last previous edition approved in 2014 as D3258 04(2014).DOI:10.1520/D3258-04R19.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual B
15、ook of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized
16、principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 medium using the camelhair brush wet with odorless mineralspirits.Repeat the process until most of the excess is removed.Then continue to remove more of the excess by applyingmineral spirits directly from the wash bottle to the area abovethe stain so that it flows across
