ASTM D1238-20

Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion Plastometer

SIGNIFICANCE AND USE
5.1 This test method is particularly useful for quality control tests on thermoplastics.  
5.2 The data produced by this test method serves to indicate the uniformity of the flow rate of the polymer as made by an individual process. It is not to be used as an indication of uniformity of other properties without valid correlation with data from other tests.  
5.3 The flow rate obtained with the extrusion plastometer is not a fundamental polymer property. It is an empirically defined parameter critically influenced by the physical properties and molecular structure of the polymer and the conditions of measurement. The rheological characteristics of polymer melts depend on a number of variables. It is possible that the values of these variables occurring in this test will differ substantially from those in large-scale processes, which would result in data that does not correlate directly with processing behavior.  
5.4 Measure the flow rate of a material using any of the conditions listed for the material in X4.1. For many materials, there are specifications that require the use of this test method, but with some procedural modifications that take precedence when adhering to the specification. Therefore, it is advisable to refer to that material specification before using this test method. Table 1 in Classification D4000 lists the ASTM materials standards that currently exist. An alternative test method for poly (vinyl chloride) (PVC) compounds is found in Test Method D3364.  
5.5 Additional characterization of a material can be obtained if more than one condition is used. In the case that two or more conditions are employed, a Flow Rate Ratio (FRR) is obtained by dividing the flow rate at one condition by the flow rate at another condition. Procedure D provides one method to measure more than one condition in a single charge.  
5.6 Frequently, variations in test technique, apparatus geometry, or test conditions, which defy all but the most careful scrutiny, exist...
SCOPE
1.1 This test method covers the determination of the rate of extrusion of molten thermoplastic resins using an extrusion plastometer.  
1.2 The values stated in SI units are to be regarded as standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
Note 1: This standard and ISO 1133 address the same subject matter, but differ in technical content.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Historical
• Publication Date: 30-Jun-2020
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.30 - Thermal Properties

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D1238 − 20
Standard Test Method for
Melt Flow Rates of Thermoplastics by Extrusion
1
Plastometer
This standard is issued under the fixed designation D1238; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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* E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to
1.1 This test method covers the determination of the rate of
Determine the Precision of a Test Method
extrusion of molten thermoplastic resins using an extrusion
2.2 ANSI Standard:
plastometer.
3
B46.1 on Surface Texture
1.2 The values stated in SI units are to be regarded as
2.3 ISO Standard:
standard.
ISO 1133 Determination of the Melt-Mass Flow Rate (MFR)
1.3 This standard does not purport to address all of the
and the Melt Volume-Flow Rate (MVR) of Thermoplas-
3
safety concerns, if any, associated with its use. It is the
tics
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- 3. Terminology
mine the applicability of regulatory limitations prior to use.
3.1 Terms used in this standard are defined in accordance
with Terminology D883, unless otherwise specified. For terms
NOTE 1—This standard and ISO 1133 address the same subject matter,
but differ in technical content.
relating to precision and bias and associated issues, the terms
used in this standard are defined in accordance with Terminol-
1.4 This international standard was developed in accor-
ogy E456.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4. Summary of Test Method
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4.1 After a specified preheating time, resin is extruded
Barriers to Trade (TBT) Committee.
through a die with a specified length and orifice diameter under
prescribed conditions of temperature, load, and piston position
2. Referenced Documents
in the barrel. Four procedures are described. Comparable
2
results have been obtained by these procedures in interlabora-
2.1 ASTM Standards:
tory round-robin measurements of several materials and are
D618 Practice for Conditioning Plastics for Testing
described in Section 16.
D883 Terminology Relating to Plastics
D3364 Test Method for Flow Rates for Poly(Vinyl Chloride)
4.2 Procedure A is used to determine the melt flow rate
with Molecular Structural Implications
(MFR) of a thermoplastic material. The units of measure are
D4000 Classification System for Specifying Plastic Materi-
grams of material/10 minutes (g/10 min). It is based on the
als
measurement of the mass of material that extrudes from the die
D5947 Test Methods for Physical Dimensions of Solid
over a given period of time. It is generally used for materials
Plastics Specimens
having melt flow rates that fall between 0.15 and 50 g/10 min
(see Note 2).
4.3 Procedure B is an automatically timed measurement
1
This test method is under the jurisdiction of ASTM Committee D20 on Plastics
used to determine the melt flow rate (MFR) as well as the melt
and is the direct responsibility of Subcommittee D20.30 on Thermal Properties
(Section D20.30.08). volume rate (MVR) of thermoplastic materials. MFR measure-
Current edition approved July 1, 2020. Published August 2020. Originally
ments made with Procedure B are reported in g/10 minutes.
approved in 1965. Last previous edition approved in 2013 as D1238 - 13. DOI:
MVR measurements are reported in cubic centimeters/ten
10.1520/D1238-20.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D1238 − 20
3
minutes (cm /10 min). Procedure B measurements are based method. Table 1 in Classification D4000 lists the ASTM
on the determination of the volume of material extruded from materials standards that currently exist. An alternative test
the die over a given period of time. The volume is converted to method
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D1238 − 13 D1238 − 20
Standard Test Method for
Melt Flow Rates of Thermoplastics by Extrusion
1
Plastometer
This standard is issued under the fixed designation D1238; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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 of extrusion of molten thermoplastic resins using an extrusion
plastometer. After a specified preheating time, resin is extruded through a die with a specified length and orifice diameter under
prescribed conditions of temperature, load, and piston position in the barrel. Four procedures are described. Comparable results
have been obtained by these procedures in interlaboratory round-robin measurements of several materials and are described in
Section 15.
1.2 Procedure A is used to determine the melt flow rate (MFR) of a thermoplastic material. The units of measure are grams of
material/10 minutes (g/10 min). It is based on the measurement of the mass of material that extrudes from the die over a given
period of time. It is generally used for materials having melt flow rates that fall between 0.15 and 50 g/10 min (see Note 1).
1.2 Procedure B is an automatically timed measurement used to determine the melt flow rate (MFR) as well as the melt volume
rate (MVR) of thermoplastic materials. MFR measurements made with Procedure B are reported in g/10 minutes. MVR
3
measurements are reported in cubic centimetres/ten minutes (cm /10 min). Procedure B measurements are based on the
determination of the volume of material extruded from the die over a given period of time. The volume is converted to a mass
measurement by multiplying the result by the melt density value for the material (see The values stated in SI units are to be
regarded as standard.Note 2). Procedure B is generally used with materials having melt flow rates from 0.50 to 1500 g/10 min.
1.4 Procedure C is an automatically timed measurement used to determine the melt flow rate (MFR) of polyolefin materials. It
is generally used as an alternative to Procedure B on samples having melt flow rates greater than 75 g/10 min. Procedure C involves
the use of a modified die, commonly referred to as a “half-die,” which has half the height and half the internal diameter of the
standard die specified for use in Procedures A and B thus maintaining the same length to diameter ratio. The test procedure is
similar to Procedure B, but the results obtained with Procedure C shall not be assumed to be half of those results produced with
Procedure B.
1.5 Procedure D is a multi-weight test commonly referred to as a “Flow Rate Ratio” (FRR) test. Procedure D is designed to allow
MFR determinations to be made using two or three different test loads (either increasing or decreasing the load during the test)
on one charge of material. The FRR is a dimensionless number derived by dividing the MFR at the higher test load by the MFR
at the lower test load. Results generated from multi-weight tests shall not be directly compared with results derived from Procedure
A or Procedure B.
1
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.30 on Thermal Properties (Section
D20.30.08).
Current edition approved Aug. 1, 2013July 1, 2020. Published August 2013August 2020. Originally approved in 1965. Last previous edition approved in 20102013 as
D1238 - 10.D1238 - 13. DOI: 10.1520/D1238-13.10.1520/D1238-20.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D1238 − 20
NOTE 1—Polymers having melt flow rates less than 0.15 or greater than 900 g/10 min may be tested by the procedures in this test method; however,
precision data have not been developed.
NOTE 2—Melt 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. See Table
3.
NOTE 3—This test method and ISO 1133 address the same subject matter, but differ in technical content.
1.3 This standard does not purport to address all of the safety concerns, if a
...