ASTM_D_2621_-_87_2016.pdf

Designation:D262187(Reapproved 2016)Standard Test Method forInfrared Identification of Vehicle Solids From Solvent-Reducible Paints1This standard is issued under the fixed designation D2621;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 qualitative characterizationor identification of separated paint vehicle solids by infraredspectroscopy within the limitations of infrared spectroscopy.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prior to use.2.Referenced Documents2.1 ASTM Standards:2D1467 Guide for Testing Fatty Acids Used in ProtectiveCoatings(Withdrawn 2003)3D1962 Test Method for Saponification Value of Drying Oils,Fatty Acids,and Polymerized Fatty Acids(Withdrawn2004)3D2372 Practice for Separation of Vehicle From Solvent-Reducible PaintsE131 Terminology Relating to Molecular SpectroscopyE275 Practice for Describing and Measuring Performance ofUltraviolet and Visible Spectrophotometers3.Terminology3.1 Definitions:3.1.1 For definitions of terms and symbols,refer to Termi-nology E131.4.Summary of Test Method4.1 Infrared spectra are prepared from dried films of isolatedpaint vehicles.Vehicle types are identified by comparing thespectra to a collection of reference infrared spectra.5.Significance and Use5.1 The ability to qualitatively identify paint vehicles isuseful for characterizing unknown or competitive coatings,forcomplaint investigations,and for in-process control.6.Apparatus6.1 SpectrophotometerA recording double-beam infraredspectrophotometer with a wavelength range from at least 2.5 to15 m and a spectral resolution of at least 0.04 m over thatrange.See Practice E275.6.2 Demountable Cell Mount,with NaCl window.6.3 Vacuum Drying Oven thermostatically controlled tooperate at 60 6 2C.A water aspirator vacuum source issatisfactory.6.4 Oven,Gravity or Forced Draft,capable of maintainingtemperature from 105 to 110C.7.Procedure7.1 Place the vehicle,separated from the paint in accordancewith Practice D2372,on a NaCl window and spread to form auniform film.Make sure that the thickness of the film is suchthat when the infrared spectrum is recorded,the transmittanceof the strongest band falls between 5 and 15%(Note).Dry thefilm in an oven at 105 to 110C for 15 min and cool in adesiccator.Inspect the film visually for defects such as bubbles,wrinkles,contamination,etc.If defects are present,cast an-other film.If easily oxidizable substances are present such astung,oiticica,or linseed oils,make sure that the film is dried at60 6 2C in a vacuum oven for 1 h.If solvents of low volatilitysuch as cyclohexanone or isophorone are present,the film mayneed to be dried for several hours in a 60C vacuum oven.NOTE1Numerous procedures and variations may be used to obtain afilm on which to prepare a suitable spectrum.These include liquidmounting between two NaCl plates,transmission through free films,andreflectance from highly polished surfaces.7.2 Immediately record the infrared spectrum from 2.5 to 15m so that a spectral resolution of 0.04 m is maintainedthroughout that range(methods for achieving this resolutionwill vary according to the directions of the manufacturer of theinstrument used).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 Dec.1,2016.Published December 2016.Originallyapproved in 1967.Last previous edition approved in 2011 as D2621 87(2011).DOI:10.1520/D2621-87R16.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.3 Compare the spectrum obtained with reference spectraprepared from nonvolatile vehicles of known composition(seeAnnex A1)or consult other published spectra available in theliterature(Annex A3).Interpret the spectrum on the basis ofavailable information,recognizing certain limitations of infra-red spectroscopy,and qualifying the interpretation accordingly(Annex A2).8.Keywords8.1 infrared spectra;paint binders;solvent reducible paintANNEXES(Mandatory Information)A1.INFRARED SPECTRA OF NONVOLATILE VEHICLES OF KNOWN COMPOSITIONA