ASTM_D_4662_-_20.pdf

Designation:D466220Standard Test Methods forPolyurethane Raw Materials:Determination of Acid andAlkalinity Numbers of Polyols1This standard is issued under the fixed designation D4662;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.Scope*1.1 These test methods measure the acidic and basic con-stituents in polyols and other materials of high acidity oralkalinity that are soluble in mixtures of toluene and ethylalcohol.These test methods do not apply to polyethers.(SeeNote 1.)1.2 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE1There is no known ISO equivalent to this standard.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization 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:2D883 Terminology Relating to PlasticsD1193 Specification for Reagent WaterE456 Terminology Relating to Quality and StatisticsE2935 Practice for Conducting Equivalence Testing inLaboratory Applications3.Terminology3.1 DefinitionsTerms used in this standard are defined inaccordance with Terminology D883,unless otherwise speci-fied.For terms relating to precision and bias and associatedissues,the terms used in this standard are defined in accordancewith Terminology E456.3.2 Definitions of Terms Specific to This Standard:3.2.1 acid number,nthe quantity of base,expressed inmilligrams of potassium hydroxide,that is required to titrateacidic constituents present in 1 g of sample.3.2.2 alkalinity number,nthe quantity of base,expressedas milligrams of potassium hydroxide,present in 1 g of sample.4.Summary of Test Method4.1 The sample is dissolved in a mixture of toluene andethyl alcohol.The resulting single-phase solution is titrated atroom temperature with alcoholic potassium hydroxidesolution,to the end point indicated by the color change ofadded phenolphthalein.Alkalinity numbers are determined byback-titration after adding excess hydrochloric acid.The end-point of these titrations also can be determined potentiometri-cally.5.Significance and Use5.1 These test methods are suitable for quality control,asspecification tests,and for research.The acid and alkalinitynumbers indicate the extent of a reaction with acids.The resultsare measures of batch-to-batch uniformity and are typicallyused as correction factors in calculating hydroxyl number.6.Reagents and Materials6.1 Purity of ReagentsUse reagent-grade chemicals in alltests.Unless otherwise indicated,it is intended that all reagentsconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society where suchspecifications are available.3Other grades are allowed,pro-vided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.1These test methods are under the jurisdiction of ASTM Committee D20 onPlastics and are the direct responsibility of Subcommittee D20.22 on CellularMaterials-Plastics and Elastomers.Current edition approved July 1,2020.Published July 2020.Originally approvedin 1987.Last previous edition approved in 2015 as D4662-15.DOI:10.1520/D4662-20.2For 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.*A Summary 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 StatesThis international standard was developed in accordance with internationally recognized 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.6.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water as defi