ASTM_D_1979_-_97.pdf

Designation:D 1979 97Standard Test Method forFree Formaldehyde Content of Amino Resins1This standard is issued under the fixed designation D 1979;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of freeformaldehyde in amino resins and their aqueous and non-aqueous solutions.Amino resin-free formaldehyde levels fromabout 0.02 to 5.0%can be determined by this test method.Theapplicability of this test method to other matrices is unknown.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2D 1959 Test Method for Iodine Value of Drying Oils andFatty Acids33.Summary of Test Method3.1 Specimens are mixed with borate buffer solution and icewater,then kept cool in an ice bath.Excess sodium sulfite isadded to consume free formaldehyde as follows:CH2O 1 Na2SO31 H2O HOCH2SO3Na 1 NaOH(1)3.2 The excess sodium sulfite is removed by titration withiodine using starch as the indicator as follows:Na2SO31 I21 H2O Na2SO41 2 HI(2)3.3 The sodium sulfite-formaldehyde complex is then de-composed with sodium carbonate to quantitatively regeneratesodium sulfite and formaldehyde as follows:HOCH2SO3Na 1 Na2CO3 CH2O 1 Na2SO31 NaHCO3(3)3.4 The liberated sodium sulfite is titrated with iodine(Eq 2)and free formaldehyde is calculated from this second iodinetitration.4.Significance and Use4.1 The amount of free formaldehyde in amino resins maybe of concern to both producer and user,as its presence in airabove threshold amounts may produce objectionable odors andirritant effects.This test method can be useful for evaluatingsuppliers products and for quality control.5.Apparatus5.1 Analytical Balance,60.1 mg.5.2 Magnetic Stirrer and Stir BarA“heavy duty”mag-netic stirrer is necessary.5.3 Buret,50 mL manual or electronic.Manual buretsshould be of the type designed to minimize the exposure ofreagent to air.Electronic burets are preferred.5.4 Beakers,glass,100 mL,600 mL,and 1500 mL.5.5 Stopwatch or Timer.5.6 Graduated Cylinders,glass,50 mL and 250 mL.5.7 Glass Pipet,2 mL.5.8 Thermometer,subdivision 1C.6.Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the reagent is of sufficienthigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water as definedby Type II of Specification D 1193.6.3 Acetic Acid Solution(1.0 M)Dissolve 60 mL ofglacial acetic acid(CH3CO2H)in water and dilute to 1 L.6.4 Boric Acid Buffer SolutionPrepare a sodium hydrox-ide solution(1.0 M)by dissolving 40 g of sodium hydroxide(NaOH)in water and diluting to 1 L.Dissolve 12.39 g of boricacid(H3BO3)in 100 mL of 1.0 M NaOH,then dilute to 1 L.Maintain temperature at 0C in an ice bath.The pH at 0Cshould be 9.4(glass electrode).6.5 Ice,finely crushed.6.6 Iodine Solution(0.1 N)Dissolve 40 g of iodate freepotassium iodide in 25 mL of water in a 100-mL beaker.Weigh1This test method is under the jurisdiction of ASTM Committee D-1 on Paintand Related Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.33 on Polymers and Resins.Current edition approved Nov.10,1997.Published June 1998.Originallypublished as D 1979-91.Last previous edition D 1979-91(l997).2Annual Book of ASTM Standards,Vol 11.01.3Annual Book of ASTM Standards,Vol 06.03.4Reagent 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.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMout 12.6905 g of dry re-sublimed iodine and add to the beaker.Stir until the iodine is dissolved and dilute to 1 L with water.Store iodine titrant in the dark.This reagent can be purchasedas a standardized solution or must be standardized againstsodium thiosulfate.6.7 Methylene Chloride(CH2Cl2)Cool to 0C in an