ASTM_D_2230_-_96_2012.pdf

Designation:D223096(Reapproved 2012)Standard Test Method forRubber PropertyExtrudability of UnvulcanizedCompounds1This standard is issued under the fixed designation D2230;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 determination of the extrud-ability of unvulcanized SBR and NBR rubber compoundsthrough a screw-type extruder equipped with ASTM ExtrusionDie,Garvey type.This test method is designed to allow theobservation of the appearance and contours of the extrusion.Rating systems are provided along with recipes for compoundsof known extrusion characteristics.The utility of the testmethod for evaluating rubbers or compounding materials otherthan those listed has not been established.Since extrusionmachines differ among laboratories,the procedure includestechniques that minimize differences between machines.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:2D3182 Practice for RubberMaterials,Equipment,and Pro-cedures for Mixing Standard Compounds and PreparingStandard Vulcanized SheetsD3185 Test Methods for RubberEvaluation of SBR(Styrene-Butadiene Rubber)Including Mixtures With OilD3187 Test Methods for RubberEvaluation of NBR(Acrylonitrile-Butadiene Rubber)2.2 ASTM Adjuncts:Appearance Ratings Photographs33.Summary of Test Method3.1 A standard compound is prepared and extruded througha specially shaped die that produces an extrusion having acombination of relatively flat surfaces,sharp corners,and thinsections.The operating conditions are varied until a satisfac-tory extrusion of the standard compound is obtained.The testcompound is then extruded,using the conditions justestablished,and the nature of the extrusion is rated visually forsmoothness,sharp corners,and integrity of thin sections.4.Significance and Use4.1 One objective in the extrusion of rubber compounds isto obtain a smooth extrusion that closely reproduces thecontours of the extrusion die.This test method provides for asubjective determination of this under controlled conditions.As the rating is subjective,it does not lend itself readily toincorporation as a specification requirement.It does not mea-sure other aspects of extrudability such as rate of extrusion ordie swell in a quantitative manner.5.Apparatus5.1 Mill,150 by 300 mm(6 by 12 in.),as described inPractice D3182.5.2 DieASTM Extrusion Die,Garvey type,conforming tothe dimensions and shape shown in Fig.1 shall be used.NOTE1Good precision in the manufacture of the opening in the diecan be attained by ultrasonic machining.The die should be replaced whena dimension has changed by 0.02 mm(0.001 in.)from its original valueor if the die is damaged.5.3 AdapterA hollow,cone-shaped ring insert taperedwith an angle of 30 6 15(shown in Fig.2)shall be used withthe die to contour the interior of the extruder head.This willreduce turbulent flow of the rubber.5.4 ExtruderA screw-type laboratory extruder having ascrew diameter of 50 mm or less and which will accommodate1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.12 on Processability Tests.Current edition approved May 1,2012.Published May 2012.Originallyapproved in 1963.Last previous edition approved in 2007 as D2230 96(2007).DOI:10.1520/D2230-96R12.2For 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.3Glossy prints of Figs.3 and 4 are available at a nominal cost from ASTMInternational Headquarters.Order Adjunct No.ADJD2230.Original adjunct pro-duced in 1986.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 the specified die may be used.The distance between the end ofthe screw and the die shall be from 1 to 2 times the diameterof the screw,the ratio of the length to diameter of the screwshall be 5:1 or greater,and the compression ratio shall be 1:1.The use of breaker plates,screens,or spiders in the extruder isnot recommended.Solid or hollow screws are acceptable;however,fluid temperature shall be controlled in hollowscrews.5.4.1 The extruder shall be equipped with devices capableof monitoring the temperature of the barrel,the head,thedischarged heating fluid from