ASTM_D_4295_-_89_2021.pdf

Designation:D429589(Reapproved 2021)Standard Classification forRubber Compounding MaterialsZinc Oxide1This standard is issued under the fixed designation D4295;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 system covers the compounding ma-terial commercially known as zinc oxide.The types of zincoxide used in the rubber industry are related to the productionprocess used.Typical chemical and physical properties areincluded.1.2 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:2D280 Test Methods for Hygroscopic Moisture(and OtherMatter Volatile Under the Test Conditions)in PigmentsD3037 Test Method for Carbon BlackSurface Area byNitrogen Adsorption(Withdrawn 1999)3D3280 Test Methods for Analysis of White Zinc PigmentsD4075 Test Methods for Rubber Compounding MaterialsFlame Atomic Absorption AnalysisDetermination ofMetalsD4315 Test Methods for Rubber Compounding MaterialZinc Oxide3.Significance and Use3.1 Zinc oxide is an important rubber compounding mate-rial.It is used to activate the organic accelerators to increasethe rate of vulcanization and to enhance physical properties.Itis also a vulcanizing agent for halogen-containing elastomers.4.Classification of Zinc Oxides by Types4.1 American Process or Direct TypeWhen zinc oxide ismanufactured by the reduction and reoxidation of a zinc-bearing material,such as a zinc ore by a carbonaceous fuel,itis called American process or direct type.American processzinc oxide is produced with widely varying chemical propertiesand physical characteristics.Nodular-type particle shape,asobserved by the light microscope,is generally preferred forrubber compounding.Due to wide variations in the materialprocessed and in the process itself,the properties of Americanprocess zinc oxide can only be characterized in a general way.4.2 French Process or Indirect TypeWhen zinc oxide ismanufactured by the burning of zinc vapor(produced byboiling zinc metal in a retort or zinc boiler),it is called Frenchprocess or indirect type.It is characterized by a high degree ofchemical purity resulting from the use of high purity(99.9%zinc).As generally produced,the particles are nodular in shapeas observed by the light microscope.4.3 Secondary Zinc Oxide Type:4.3.1 ChemicalWhen zinc oxide is manufactured as aby-product of a chemical reaction,it is considered a secondarytype.The chemical and physical properties can vary widelydepending on the raw material source and the type of reaction.4.3.2 MetallurgicalWhen zinc oxide is manufacturedfrom burning zinc vapor produced by boiling die cast scrapzinc,galvanized zinc dross,or other scrap zinc units withoutpurification,it is considered a secondary type.The chemicalpurity can vary widely and is dependent on the purity of thefeed metal.5.Composition and Properties5.1 Typical properties for untreated zinc oxide by types aredescribed in Table 1.5.2 Treated Zinc OxideZinc oxide for use in rubber isoften surface treated,most frequently with a fatty acid such aspropionic acid.5.2.1 A fatty acid treated zinc oxide will typically containabout 0.5%less zinc oxide than the corresponding untreatedgrade.5.2.2 The typical fatty acid treated zinc oxide shows agreater heat loss,about 0.2%,than the corresponding untreatedgrade due to partial vaporization of the fatty acid.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 December 2021.Originallyapproved in 1983.Last previous edition approved in 2017 as D4295 89(2017).DOI:10.1520/D4295-89R21.2For 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 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.1?ASTM International takes no position r