1、Designation:D401702(Reapproved 2015)Standard Test Method forWater in Paints and Paint Materials by Karl Fischer Method1This standard is issued under the fixed designation D4017;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year
2、 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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method is applicable to
3、all paints and paintmaterials,including resins,monomers,and solvents,with theexception of aldehydes and certain active metals,metal oxides,and metal hydroxides.While the evaluation was limited topigmented products containing amounts of water in the 30 to70%range,there is reason to believe that highe
4、r and lowerconcentrations can be determined by this test method.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is the
5、responsibility 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.Specific hazardstatements are given in Section 7.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD3
6、960 Practice for Determining Volatile Organic Compound(VOC)Content of Paints and Related CoatingsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals(Withdrawn 2009)3E203 Test Method for Water Using Volumetric Karl FischerTitratio
7、n2.2 Other Standard:EPAFederal Reference Method 24 Determination of VolatileMatter Content,Density,Volume Solids,and WeightSolids of Surface Coatings43.Summary of Test Method3.1 The material is dissolved in a suitable solvent,andtitrated directly with standardized Karl Fischer reagent,to anelectrome
8、tric end point.The sluggish reaction with water inpyridineisacceleratedwithachemicalcatalyst,1-ethylpiperidine.3.1.1 Karl Fischer reagent is a mixture of iodine,amine,sulfur dioxide,and an alcohol.In the reaction with water,iodine is reduced to hydrogen iodide.Once all the water isconsumed,the appea
9、rance of free iodine is detected electro-chemically and the titration is stopped.The following depictsthe chemistry that takes place:ROH+SO2+RN (RNH)SO3RH2O+I2+(RNH)SO3R+2RN(RNH)SO4R+2(RNH)I3.2 In classical Karl Fischer titrations the base used ispyridine,and the solvent either methanol or methoxy e
10、thanol.In order to accelerate the reaction when pyridine is used,1-ethylpiperidine is used as a catalyst/buffer.The additionalbuffer capacity is usually already built in to most nonpyridinebased reagents such as hydranal(see Hydranal Manual).54.Significance and Use4.1 Control of water content is oft
11、en important in control-ling the performance of paint and paint ingredients,and it iscritical in controlling volatile organic compound(VOC)con-tent.4.2 Paint materials are often insoluble in common KarlFischer solvents such as methanol.Pyridine has been found tobe a nearly universal solvent for thes
12、e materials;however,theKarl Fischer reaction is too slow in that solvent at roomtemperature.To speed it up,1-ethylpiperidine is added at 5%as a buffer,or“catalyst.”4.3 For nonpyridine-based reagents,a number of differentsolvent systems are available to increase solubility and tominimize interference
13、s from ketones and aldehydes.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved June 1,2015.Publis
14、hed June 2015.Originallyapproved in 1981.Last previous edition approved in 2008 as D4017 02(2008)1.DOI:10.1520/D4017-02R15.2For 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 t
15、o the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from U.S.Government Printing Office Superintendent of Documents,732 N.Capitol St.,NW,Mail Stop:SDE,Washington,DC 20401,http:/www.access.gpo.gov.5Ava
16、ilable from Hoechst Celanese Corporation,Hydranal Technical Center,U.S.Highway 43,Bucks,AL 36512.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Apparatus5.1 Karl Fischer Apparatus,manual or automatic,encom-passed by the description in Test Method E203.Apparatusshould be equipped with a 25-mL buret,ClassA,or equivalent.5.2 Syringe,100-L capacity,with needle.5.3 Syringes,1-mL and 10-mL capacity,without needle,butequipped with caps.6.
