ASTM_D_6902_-_04_2011.pdf

Designation:D690204(Reapproved 2011)Standard Test Method forLaboratory Measurement of Formaldehyde Evolved Duringthe Curing of Melamine-Formaldehyde-Based Coatings1This standard is issued under the fixed designation D6902;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 is for the determination of formalde-hyde evolved from melamine-formaldehyde-based coatingsduring the cure step.The results may be used to determine the“cure formaldehyde”evolved from a sample under controlledlaboratory conditions.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 This test method is capable of measuring from 500 g/gto 22 000 g formaldehyde/g dry coating under the testconditions specified(3 000 ml/min total flow,50 ml/minDNPH tube flow).The ratio of total flow to DNPH tube flowcould be adjusted to extend the range of the method.1.4 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for Industrial Grade Toluene(Withdrawn1989)3D1979 Test Method for Free Formaldehyde Content ofAmino Resins(Withdrawn 2006)3D6191 Test Method for Measurement of Evolved Formalde-hyde from Water Reducible Air-Dry CoatingsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 cure formaldehyde,nthe formaldehyde generated asthe result of a chemical reaction during coating curing.3.1.2 free formaldehyde,nthe residual formaldehyde in acoating due to the raw materials.4.Summary of Test Method4.1 Approximately 0.2 g of coating formulation is placed inan aluminum foil pan,dried in a vacuum oven at 40C(toremove free formaldehyde and solvents)and then baked at theoptimum process cure temperature for 30 min.Formaldehydeemissions are collected from the cure chamber on a DNPH/Silica tube,which is then extracted and the extract analyzed byHPLC/UV.The amount of formaldehyde evolved from thecoating during the cure step is calculated on both a wet-weightand dry-weight basis.The test is run in triplicate plus a blankand system standard.5.Significance and Use5.1 This test method measures the amount of formaldehydethat is evolved from a coating containing melamine-formaldehyde resin(s)during cure at elevated temperature.Cure formaldehyde results from a side-reaction during cross-linkingoffunctionalizedpolymerswithmelamine-formaldehyde resins.Cure formaldehyde is evolved in the finalbake or cure oven,when the coating temperature is highenough to initiate cross-linking.Formaldehyde can be releasedfrom a coating during application,solvent flash-off and cure.Free formaldehyde is primarily evolved during coating appli-cation and solvent flash-off.Test Method D1979 measures“free formaldehyde”in amino resins and Test Method D6191measures formaldehyde evolved from coatings at ambienttemperature.This method measures only the formaldehydereleased during heat cure,which is primarily“cure formalde-hyde.”5.2 This test method is not intended to duplicate the evolvedformaldehyde from an industrial process,but serves as areproducible comparative laboratory evaluation.5.3 This test method has not been evaluated with catalyzedcoating systems that cure at or below 40C,such as those used1This 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 June 1,2011.Published June 2011.Originallyapproved in 2003.Last previous edition approved in 2004 as D6902 041.DOI:10.1520/D6902-04R11.2For 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 by the wood-finishing industry,and would likely requirespecial adaptation for this application.6.Apparatus6.1 High Pressure Liquid Chromatograph(HPLC),either agradient or isocratic system.A gradient system is preferredwhen other aldehydes or ketones are present.NOTE1The system shall be equipped with a temperature-controlledcolumn oven.A liquid autosampler is optional.6.2