ASTM_D_3493_-_16.pdf

Designation:D349316Standard Test Method forCarbon BlackOil Absorption Number of CompressedSample(COAN)1This standard is issued under the fixed designation D3493;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 procedure for the mechani-cal compression of a carbon black sample and the determina-tion of the oil absorption number of the compressed sample.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 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:2D1765 Classification System for Carbon Blacks Used inRubber ProductsD1799 Practice for Carbon BlackSampling PackagedShipmentsD1900 Practice for Carbon BlackSampling Bulk Ship-mentsD2414 Test Method for Carbon BlackOil AbsorptionNumber(OAN)D4821 Guide for Carbon BlackValidation of Test MethodPrecision and BiasD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3.Summary of Test Method3.1 A sample of carbon black is compressed four times in acompression cylinder at a pressure of 165 MPa(24 000 psi)and then tested in an absorptometer to determine the oilabsorption number.3.2 n-Dibutyl phthalate,paraffin,or EFA oil is added bymeans of a constant-rate buret to the compressed sample ofcarbon black in the mixer chamber of an absorptometer.As thesample absorbs the oil,the mixture changes from a free-flowing state to one of a semiplastic agglomeration,with anaccompanying increase in viscosity.This increased viscosity istransmitted to the torque-sensing system of the absorptometer.When the viscosity of the mixture reaches a predeterminedtorque level,the absorptometer and buret will simultaneouslyshut off.The volume of oil added is read from the directreading buret.The volume of oil per unit mass of carbon blackis the oil absorption number.Either DBP,paraffin,or EFA oilis acceptable for use with many standard pelleted grades ofN-series carbon blacks found in Classification D1765.COANtesting using paraffin or EFA oil on some specialty blacks andpowder blacks may result in significant differences whencompared to COAN testing using DBP oil.Referee testingbetween suppliers and users should use DBPoil until such timethat precision data is available for paraffin and EFA oils.4.Significance and Use4.1 The oil absorption number of a carbon black is related tothe processing and vulcanizate properties of rubber compoundscontaining the carbon black.4.2 The difference between the regular oil absorption num-ber and the oil absorption number of compressed sample issome measure of the stability of the structure of the carbonblack.5.Apparatus35.1 Balance,analytical,0.01-g sensitivity.1This test method is under the jurisdiction of ASTM Committee D24 on CarbonBlack and is the direct responsibility of Subcommittee D24.11 on Carbon BlackStructure.Current edition approved Jan.1,2016.Published January 2016.Originallyapproved in 1976.Last previous edition approved in 2014 as D3493 14.DOI:10.1520/D3493-16.2For 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.3Each apparatus is to be operated and maintained in accordance with themanufacturers directions for optimum performance.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2 Oven,gravity-convection type,capable of maintaining125C 6 5C.5.3 Carbon Black Press,capable of compressing a 25-gsample to 165 MPa(24 000 psi).45.4 Absorptometer,5equipped with a constant-rate buret thatdelivers 67 6 0.4 mm3/s(4 6 0.024 cm3/min).5.5 Spatula,rubber,100 mm.5.6 Sieve,850 m(U.S.No.20),approximately 125-mm(5-in.)diameter with receiver pan.5.7 Brush,approximately 40 mm(1.5 in.),stiff bristle.5.8 Desiccator.6.Reagent and Standards6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.6Other grades may beused,provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.6.2 n-Dibutyl Phthalate,having a density of 1.042 to1.047 mgm3at 25