ASTM_D_1238_-_13.pdf

Designation:D123813Standard Test Method forMelt Flow Rates of Thermoplastics by ExtrusionPlastometer1This standard is issued under the fixed designation D1238;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 This test method covers the determination of the rate ofextrusion of molten thermoplastic resins using an extrusionplastometer.After a specified preheating time,resin is extrudedthrough a die with a specified length and orifice diameter underprescribed conditions of temperature,load,and piston positionin the barrel.Four procedures are described.Comparableresults have been obtained by these procedures in interlabora-tory round-robin measurements of several materials and aredescribed in Section 15.1.2 Procedure A is used to determine the melt flow rate(MFR)of a thermoplastic material.The units of measure aregrams of material/10 minutes(g/10 min).It is based on themeasurement of the mass of material that extrudes from the dieover a given period of time.It is generally used for materialshaving melt flow rates that fall between 0.15 and 50 g/10 min(see Note 1).1.3 Procedure B is an automatically timed measurementused to determine the melt flow rate(MFR)as well as the meltvolume rate(MVR)of thermoplastic materials.MFR measure-ments made with Procedure B are reported in g/10 minutes.MVR measurements are reported in cubic centimetres/tenminutes(cm3/10 min).Procedure B measurements are basedon the determination of the volume of material extruded fromthe die over a given period of time.The volume is converted toa mass measurement by multiplying the result by the meltdensity value for the material(see Note 2).Procedure B isgenerally used with materials having melt flow rates from 0.50to 1500 g/10 min.1.4 Procedure C is an automatically timed measurementused to determine the melt flow rate(MFR)of polyolefinmaterials.It is generally used as an alternative to Procedure Bon samples having melt flow rates greater than 75 g/10 min.Procedure C involves the use of a modified die,commonlyreferred to as a“half-die,”which has half the height and halfthe internal diameter of the standard die specified for use inProcedures A and B thus maintaining the same length todiameter ratio.The test procedure is similar to Procedure B,butthe results obtained with Procedure C shall not be assumed tobe half of those results produced with Procedure B.1.5 Procedure D is a multi-weight test commonly referred toas a“Flow Rate Ratio”(FRR)test.Procedure D is designed toallow MFR determinations to be made using two or threedifferent test loads(either increasing or decreasing the loadduring the test)on one charge of material.The FRR is adimensionless number derived by dividing the MFR at thehigher test load by the MFR at the lower test load.Resultsgenerated from multi-weight tests shall not be directly com-pared with results derived from Procedure A or Procedure B.NOTE1Polymers having melt flow rates less than 0.15 or greater than900 g/10 min may be tested by the procedures in this test method;however,precision data have not been developed.NOTE2Melt density is the density of the material in it molten state.It is not to be confused with the standard density value of the material.SeeTable 3.NOTE3This test method and ISO 1133 address the same subjectmatter,but differ in technical content.1.6 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D618 Practice for Conditioning Plastics for TestingD883 Terminology Relating to PlasticsD3364 Test Method for Flow Rates for Poly(Vinyl Chloride)with Molecular Structural ImplicationsD4000 Classification System for Specifying Plastic Materi-als1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.30 on Thermal Properties(Section D20.30.08).Current edition approved Aug.1,2013.Published August 2013.Originallyapproved in 1965.Last previous edition approved in 2010 as D1238-10.DOI:10.1520/D1238-13.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 E691 Practice for Conducting an Interlaboratory Study toD