ASTM_D_4660_-_12.pdf

Designation:D466012Standard Test Methods forPolyurethane Raw Materials:Determination of the IsomerContent of Toluenediisocyanate1This standard is issued under the fixed designation D4660;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 amount of toluene-2,6-diisocyanate(2,6-TDI)isomer or toluene2,4diisocyanate(2,4-TDI)isomer in mixtures of the 2,4-and 2,6-isomers oftoluenediisocyanate(TDI).Two different test methods areprovided to give accurate results over the broad range ofisomer concentrations possible.1.1.1 Test Method AApplicable to TDI samples containing5 to 95%of 2,6-TDI isomer(5 to 95%2,4-TDI isomer).1.1.2 Test Method BApplicable to TDI samples containing0 to 5%of 2,6-TDI isomer(95 to 100%2,4-TDI isomer).NOTE1These test methods are equivalent to ISO 15064.1.2 The values stated in SI units are to be regarded asstandard.1.3 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:2D883 Terminology Relating to PlasticsE180 Practice for Determining the Precision of ASTMMethods for Analysis and Testing of Industrial and Spe-cialty Chemicals(Withdrawn 2009)32.2 ISO Standard:4ISO 15064 PlasticsAromatic Isocyanates for Use in theProduction of PolyurethanesDetermination of the Iso-mer Ratio in Toluenediisocyanate3.Terminology3.1 Terminology in these test methods is in accordance withTerminology D883.3.2 Definitions of Terms Specific to This Standard:3.2.1 isomera compound having the same molecular for-mula(percentage composition and molecular weight)as an-other compound but differs in chemical or physical properties.3.2.2 isomer contentthe amount of an isomer expressed asa percentage of total 2,4 and 2,6-TDI isomer amount.4.Summary of Test Methods4.1 Both test methods are based on the quantitative mea-surement of absorption bands arising from out-of-plane C-Hdeformation vibrations of the aromatic ring.4.2 In Test Method A,the infrared spectrum of a cyclo-hexane solution of the sample is recorded in the 770 to840-cm1region.The absorbance ratio of the 805 cm1to the782 cm1band is measured and converted to percent 2,6-TDI,or percent 2,4-TDI,or both,from a previously establishedcalibration curve.4.3 In Test Method B,the absorbance of the 782-cm1bandis measured from an infrared spectrum of an undiluted sampleand then converted to percent 2,6-TDI from a previouslyestablished calibration curve.5.Significance and Use5.1 These test methods can be used for research or forquality control to determine the isomer content of toluenediisocyanates.5.2 The isomer content of a toluene diisocyanate relates toits reactivity.6.Apparatus6.1 SpectrophotometerAny single-or double-beam re-cording infrared spectrophotometer accurate to 0.2%transmis-sion and capable of resolving the two peaks of the 2,4-TDIisomer doublet at 805-815 cm1(see Fig.1).6.2 Cells,sealed sodium chloride(NaCl)liquid absorptioncells with 0.2-mm(Test Method A)and 0.1-mm(Test Method1These 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 May 1,2012.Published June 2012.Originallyapproved in 1959.Last previous edition approved in 2006 as D4660-06.DOI:10.1520/D4660-12.2For 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.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*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 States1 B)path lengths.The actual thicknesses of the cells are to beknown to 60.002 mm.6.3 Glassware,25-mL,glass-stoppered,volumetric flasks,10-mL,glass-stoppered,flasks,0.80-mL volumetric pipet,andan all-glass syringe.7.Reagents and Materials7.1 Purity of ReagentsUse reagent grade chemicals in alltests.Unless otherwise noted,all reagents conform to thespecifications of the Committee on Analytical Reagents of theAmerican Chemical Society where such specifications areavailable.5Other grades may be used,provided it is ascertainedthat the reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of