ASTM_D_3723_-_05_2011.pdf

Designation:D372305(Reapproved 2011)Standard Test Method forPigment Content of Water-Emulsion Paints by Low-Temperature Ashing1This standard is issued under the fixed designation D3723;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of 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 a procedure for the pigmentcontent determination of water-based paints.It is applicableonly to pigments that do not decompose or lose weight attemperatures below 500C.Such pigments include most metaloxides,silicates,and a majority of anhydrous inorganic salts.1.2 Many water-based paints contain pigments and organiccolorants that lose water of hydration or decompose at thistemperature.The residual ash should be carefully inspected forchanges in color or texture that could indicate a pigmentalteration and hence lead to erroneous results.Caution shouldtherefore be exercised when applying this test method tosamples containing unknown pigment compositions.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 theresponsibility 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:2D1193 Specification for Reagent Water3.Significance and Use3.1 This test method is used by paint producers and con-sumers for product process control and for product acceptance.4.Apparatus4.1 Oven,forced draft,maintained at 105 6 2C.4.2 Furnace,muffle,maintained at 450 6 25C.4.3 Syringe,5-mL.4.4 Aluminum Foil Dish,58 mm in diameter by 18 mm highwith a flat bottom.The bottom of the dish should be as nearlyflat as possible so that a uniform film is produced.5.Reagents5.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water conformingto Type III of Specification D1193.5.3 Ammonium Hydroxide4Add 1 volume of concen-trated NH4OH(sp gr 0.90)to 3 volumes of water.6.Procedure6.1 Mix samples until homogeneous,preferably on a me-chanical shaker.If air bubbles become entrapped in a sample,stir it by hand.6.2 Draw approximately 1.5 g of the test paint into a 5-mLsyringe and weigh to 1 mg.Add the paint dropwise(about 30drops)into a preweighed,tared aluminum dish that contains 2mL of water(5.2).Swirl the dish during the addition andcontinue the swirling until the specimen is completely dis-persed.Reweigh the syringe to 1 mg.Transfer between 0.4 and0.6 g of sample to the dish.If not,adjust the transferred volumeand prepare a new specimen.If the specimen agglomerates orforms a lump that cannot be dispersed,a drop or two of1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved June 1,2011.Published June 2011.Originallyapproved in 1978.Last previous edition approved in 2005 as D3723 051.DOI:10.1520/D3723-05R11.2For 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.3Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing of reagents notlisted by the American Chemical Society,see Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.4For guidance in the safe handling of ammonium hydroxide consult theManufacturing Chemists Associations Chemical Safety Data Sheet.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 ammonia(5.3)may facilitate the dispersement.If the lumpingpersists,discard the specimen and prepare a new one.Preparea duplicate specimen in the same manner.6.3 Dry the specimen and dishes in the 105 6 2C oven fora minimum of 1 h after making certain that the dishes are level.If the coating does not uniformly cover t