ASTM_D_3643_-_15.pdf

Designation:D364315Standard Test Method forAcid Number of Certain Alkali-Soluble Resins1This standard is issued under the fixed designation D3643;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 the measurement of the freeacidity present in certain alkali-soluble resins.1.2 This test method is not suitable for styrene-maleicanhydride resins.1.3 The resin manufacturer should specify whether or notthis test method may be used for his product(s).1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5 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:2D362 Specification for Industrial Grade Toluene(Withdrawn1989)3D1152 Specification for Methanol(Methyl Alcohol)D1193 Specification for Reagent WaterD3644 Test Method for Acid Number of Styrene-MaleicAnhydride Resins3.Terminology3.1 Definitions:3.1.1 acid numberthe number of milligrams of potassiumhydroxide(KOH)required to neutralize the alkali-reactivegroups in 1 g of material under the conditions of test.4.Significance and Use4.1 This test method is not appropriate for alkali-solubleresins whose acid functionality is due to incorporated anhy-drides.Variations in manufacture,storage,and possible con-tamination of anhydride functional resins may cause partialhydrolysis,or esterification,which will invalidate data fromthis test method.Anhydride functional resins should be char-acterized by Test Method D3644.4.2 This test method is used to measure a property of acidfunctionalized resins.Acid number determines the utility ofresins as well as being a significant quality control measure.5.Reagents and Materials5.1 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.4Other 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 Specification D1193.5.3 Neutral Solvent MixtureMix equal parts of denaturedalcohol and industrial toluene conforming respectively to therequirements described for SDA.3A(200 proof)and Specifi-cation D362.Neutralize the mixture using 0.1 N KOH solutionand phenolphthalein indicator solution,until the faint pinkcolor persists for 1 min.5.4 Phenolphthalein Indicator Solution(10 g/L)Dissolve1.0 g of phenolphthalein in 100 mL of denatured alcohol(SDA3A,200 proof).5.5 Potassium Hydroxide,Methyl Alcohol Solution(1mL=5.6 mg KOH)Dissolve 6.6 g of potassium hydroxide1This test method is under the jurisdiction ofASTM Committee D21 on Polishesand is the direct responsibility of Subcommittee D21.02 on Raw Materials.Current edition approved Nov.1,2015.Published November 2015.Originallyapproved in 1978.Last previous edition approved in 2010 as D3643 10.DOI:10.1520/D3643-15.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.4Reagent 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1(KOH)in 1 L of methyl alcohol conforming to the require-ments described in Specification D1152.Standardize againstNational Institute of Standards and Technology standardsample of acid potassium phthalate No.84,using phenolphtha-lein as the indicator.Do not adjust the concentration of thesolution,but calculate the milligrams of KOH per L ofsolution.6.Procedure6.1 Weigh or transfer into a 250-mL Erlenmeyer flask 0.5 gof crushed resin to the nearest 0.001 g.6.2 Add 100 mL of neutral solvent.Mix until all material isdissolved.Add 3 to 5 drops of phenolphthalein indi