ASTM_D_4924_-_21.pdf

Designation:D492421Standard Classification forPetroleum Waxes for Use in Rubber Compounding1This standard is issued under the fixed designation D4924;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 classification is intended to establish a classifica-tion system and test methods for petroleum waxes used inrubber compounding primarily as a static protective agent ormaterial for unsaturated rubbers such as styrene-butadienerubber,polyisoprene rubber,natural rubber,chloroprenerubber,acrylonitrile-butadiene rubber,and polybutadiene rub-ber.These unsaturated rubbers are subject to ozone cracking.Under certain exposure conditions,waxes retard this cracking.1.2 This classification is applicable to petroleum waxes usedas process aids in rubber compounding.It is not applicable tononpetroleum waxes such as carnuba wax,candelille wax,orceresin wax,nor to synthetic hydrocarbon waxes such aspolyethylene wax.These non-petroleum waxes display a dif-ferent behavior on gas chromatographic analysis than dopetroleum waxes.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D87 Test Method for Melting Point of Petroleum Wax(Cooling Curve)D445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids(and Calculation of Dynamic Viscos-ity)D721 Test Method for Oil Content of Petroleum WaxesD938 Test Method for Congealing Point of PetroleumWaxes,Including PetrolatumD1321 Test Method for Needle Penetration of PetroleumWaxesD1500 Test Method for ASTM Color of Petroleum Products(ASTM Color Scale)D1747 Test Method for Refractive Index of Viscous Mate-rialsD1833 Test Method for Odor of Petroleum WaxD2887 Test Method for Boiling Range Distribution of Pe-troleum Fractions by Gas ChromatographyD3944 Test Method for Solidification Point of PetroleumWaxD4419 Test Method for Measurement of Transition Tem-peratures of Petroleum Waxes by Differential ScanningCalorimetry(DSC)3.Summary of Classification3.1 The boiling point range of the petroleum wax is deter-mined by simulated distillation by gas chromatography(TestMethod D2887).If necessary,an internal standard is used todetermine the amount of material not volatile under theconditions of the chromatograph.3.2 Classification is made on the basis of the amount of thesample with normal boiling point above 538C(1000F).3.3 Further characterization is then done using other testmethods on the wax.In particular,the melting point behavior,color,odor,and viscosity when melted and refractive indexwhen melted have been found useful.4.Significance and Use4.1 Petroleum waxes in rubber compounds are commonlyused to provide protection from degradation by ozone understatic conditions,that is,when there is little or no flexing of therubber products.The mode of action for this protection is(1)migration of the wax through the rubber to the surface of theproduct and(2)the formation of an ozone impervious film onthe surface.1This classification is under the jurisdiction of ASTM Committee D11 onRubber and Rubber-like Materials and is the direct responsibility of SubcommitteeD11.20 on Compounding Materials and Procedures.Current edition approved Nov.1,2021.Published November 2021.Originallyapproved in 1989.Last previous edition approved in 2017 as D4924 89(2017).DOI:10.1520/D4924-21.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.14.2 This standard classifies the petroleum waxes on thebasis of molecular weight.In general,waxes of lower molecu-lar weight(“paraffinic”or“crystalline”)migrate through therubber more rapidly and form more brittle film than the high