ASTM_D_7588_-_11.pdf

Designation:D758811Standard Guide forFT-IR Fingerprinting of a Non-Aqueous Liquid Paint asSupplied in the Manufacturers Container1This standard is issued under the fixed designation D7588;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 guide covers the FT-IR fingerprinting of a liquidpaint as supplied in the container without the need to separatecomponents.Spectra collected using this technique have beenfound useful for paint manufacturers quality control,troubleshooting and to verify that the paint being used is the same asthe paint sample tested.This technique has been found usefulfor both single and multi-component coatings,the latter ofwhich,where each component is analyzed separately(forexample,amine cured epoxies and polyol/isocyanate ure-thanes).1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 requirements prior to use.2.Referenced Documents2.1 ASTM Standards:2D2621 Test Method for Infrared Identification of VehicleSolids From Solvent-Reducible PaintsE131 Terminology Relating to Molecular SpectroscopyE168 Practices for General Techniques of Infrared Quanti-tative AnalysisE204 Practices for Identification of Material by InfraredAbsorption Spectroscopy,Using the ASTM Coded Bandand Chemical Classification Index(Withdrawn 2014)33.Terminology3.1 DefinitionsFor definitions of terms and symbols,referto terminology in Terminology E131.4.Summary of Guide4.1 Infrared spectra are collected using an FT-IR spectro-photometer fitted with an ATR crystal,multi or single bounce.Samples are taken directly from the paint container as suppliedby the manufacturer.5.Significance and Use5.1 The ability to collect an infrared spectrum of a liquidpaint as supplied in the container from the manufacturer is ofsignificant importance when performing qualification testing.Historically,fingerprinting a material for such purpose in-volved separating the components of the paint and collectingan infrared spectrum of one or more of these components(vehicle,pigments,solvent,etc.)with Test Method D2621being used for the identification of the vehicle.This unfortu-nately provides information only on the portion of the liquidpaint analyzed whereas the technique shown in this practiceprovides a more complete picture of what is in the containerprovided.In addition,user expertise and time required tocollect a spectrum is minimal versus traditional standards.6.Apparatus6.1 SpectrophotometerAn FT-IR spectrophotometer witha wavelength range of at least 600 to 4000 cm-1and aresolution no less than 4 cm-1.6.2 Multi or Single Bounce Horizontal Attenuated TotalReflectance(ATR)TroughFor many paint samples,a 45degree single bounce Fresnel-type ZnSe crystal has been foundto provide satisfactory results for most liquid paints.Paintsamples unsuitable for this setup will exhibit many 100%absorptions not to be confused with the 100%absorptionsassociated with the spectral cutoff of the instrument optics andcrystal material.It should be noted that ATR spectra areinfluenced by the depth of penetration of the infrared wave intothe sample which can be influenced by the type of crystalmaterial.Two spectra obtained using different crystal materialscan appear different.For finite comparison of like materials it1This guide is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.21 on Chemical Analysis of Paints and Paint Materials.Current edition approved June 1,2011.Published June 1,2011.DOI:10.1520/D7588-11.2For 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 is recommended that only spectra obtained with the samecrystal material be compared.7.Procedure7.1 Ensure that the contents of the container are homoge-neous.7.2 Collect a background infrared spectrum with the ATRtrough in place.It is recommended that a new background becollected before the analysis of each sample.7.3 Fill the trough with the sample and then immediatelycollect an infrared spectrum from 600 to 4000 cm-1at aresolution of no less than 4 cm-1or as a