ASTM D2538-02(2010)
(Practice)Standard Practice for Fusion of Poly(Vinyl Chloride) (PVC) Compounds Using a Torque Rheometer
Standard Practice for Fusion of Poly(Vinyl Chloride) (PVC) Compounds Using a Torque Rheometer
SIGNIFICANCE AND USE
When PVC compounds are mixed under appropriate conditions of heat and shear, a fused mass is produced. This mass has certain melt characteristics which can be defined with a torque rheometer operated under fixed conditions of shear and temperature. The fusion characteristics of a PVC compound are manifest as fusion time, fusion torque, melt torque, melt viscosity, and heat and color stability.
A control lot is to be used as a standard against which other test results are to be compared. Test data are to be evaluated relative to the control lot.
SCOPE
1.1 This practice covers the relative fusion characteristics of poly(vinyl chloride) compounds.
1.2 The test procedures appear in the following order:
General Information
Relations
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D2538 − 02 (Reapproved 2010)
Standard Practice for
Fusion of Poly(Vinyl Chloride) (PVC) Compounds Using a
Torque Rheometer
This standard is issued under the fixed designation D2538; 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.
1. Scope 4. Summary of Practice
4.1 A sample of powder-mix compound is added to the
1.1 This practice covers the relative fusion characteristics of
poly(vinyl chloride) compounds. heated roller mixer chamber and is transformed into a fused
mass.
1.2 The test procedures appear in the following order:
4.2 The resulting torque curve can be used to determine the
Section
relative fusion time and fusion characteristics.
Fusion Test 9
Thermal Stability Test 10
5. Significance and Use
Color-Hold Stability Test 11
Shear Stability Test 12
5.1 When PVC compounds are mixed under appropriate
conditions of heat and shear, a fused mass is produced. This
1.3 The values stated in SI units are to be regarded as the
mass has certain melt characteristics which can be defined with
standard.
a torque rheometer operated under fixed conditions of shear
1.4 This standard does not purport to address all of the
and temperature. The fusion characteristics of a PVC com-
safety concerns, if any, associated with its use. It is the
pound are manifest as fusion time, fusion torque, melt torque,
responsibility of the user of this standard to establish appro-
melt viscosity, and heat and color stability.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. Specific hazards 5.2 A control lot is to be used as a standard against which
statements are given in Section 8. other test results are to be compared. Test data are to be
evaluated relative to the control lot.
NOTE 1—There are no ISO standards covering the primary subject
matter of this ASTM standard.
6. Apparatus
6.1 Microprocessor Torque Rheometer, equipped with a
2. Referenced Documents
high-shear mixer with roller-style blades, bowl-jacket
2.1 ASTM Standards:
thermocouple, stock thermocouple, and temperature recorder.
D883 Terminology Relating to Plastics
NOTE 2—Atorque rheometer without microprocessor capability can be
D1600 Terminology forAbbreviatedTerms Relating to Plas-
used to perform the fusion, thermal stability, and color hold tests.
tics
E691 Practice for Conducting an Interlaboratory Study to 6.1.1 For flexible and rigid compounds, use a Type 6 roller
head with a rotor ratio of 3 Drive: 2 Driven.
Determine the Precision of a Test Method
NOTE 3—AType 5 roller head can also be used, but the data generated
3. Terminology
cannot be compared with the Type 6 data.
3.1 Definitions—Definitions are in accordance with Termi-
6.2 Quick-Loading Powder Chute or equivalent.
nologies D883 and D1600 unless otherwise indicated.
6.3 Brass Knife.
6.4 Brass Wool or Brush.
6.5 Insulated Gloves.
This practice is under the jurisdiction ofASTM Committee D20 on Plastics and
is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials.
6.6 Balance, 500-g minimum capacity, with a 0.1-g sensi-
Current edition approved Nov. 1, 2010. Published March 2011. Originally
tivity.
approved in 1969. Last previous edition approved in 2002 as D2538 – 02.
DOI:10.1520/D2538-02R10.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Suitable equipment may be obtained from C. W. Brabender, 50 E. Wesley St.,
Standards volume information, refer to the standard’s Document Summary page on South Hackensack, NJ 07606, and Haake Buchler Instruments, 244 Saddle River
the ASTM website. Rd., Saddle Brook, NJ 07662.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2538 − 02 (2010)
6.7 Beaker, stainless steel, 400 mL.
6.8 Oven.
6.9 Aluminum Foil.
6.10 Timer.
6.11 Long-Nose Pliers.
6.12 Hand-Press Mold.
7. Materials
7.1 Poly(Vinyl Chloride) Resin.
7.2 Filter.
7.3 Lubricants.
7.4 Plasticizer.
7.5 Process-Aid.
7.6 Impact Modifier.
7.7 Stabilizer.
7.8 Pigments.
8. Hazards
8.1 Do not exceed the power capacity of the instrument, as
damage to the mixer or to the torque rheometer may result.
8.2 Do not attempt to clean or poke objects into the mixer
while it is running.
8.3 Gloves with sufficient insulation to enable the operator
FIG. 1 Torque Rheometer Curve
to handle the hot equipment should be worn when conducting
these tests.
9.3.2 Weigh a sample of the test compound in accordance
9. Fusion Test Method
with 9.3.1. With the mixer running, position the quick-loading
9.1 Compound Preparation:
chute on the roller-head mixer and pour in the sample com-
9.1.1 The compound may be beaker-mixed, blended in an
pound. Place the ram into the chute and add the weight. When
intensive mixer or a ribbon blender, or blended and pelletized.
the torque curve indicates maximum torque has been reached,
If the compound is beaker-mixed, the total weight of the
remove the loading chute and weight.
compound should equal the amount charged to the roller-head
9.3.3 Continue mixing until the melt torque achieves a
bowl.
steady state.
9.2 Equipment Preparation:
9.3.4 Stop the mixer and open the bowl. Clean the com-
9.2.1 Mount the roller head on the torque rheometer.
pound from the bowl and blades using the brass knife or wool,
9.2.2 Select a temperature/rotor speed combination that will
or both.
permit the test to be completed within a reasonable time
9.3.5 Reassemble the mixing bowl and repeat 9.3.2 – 9.3.4
constraint. Suggested combinations for several types of PVC
for additional tests. Since some cooling takes place when
compound are found in Appendix X2.
cleaning the bowl, allow sufficient time to confirm that the
9.2.3 With the mixer empty and running, zero the recording
mixing bowl has reached equilibrium at the test temperature
pen on the chart. before using again.
9.3 Procedure:
NOTE 5—The quick-loading chute should be at the same temperature at
the start of each test. Heat or cool as required.
9.3.1 Determine the sample size to be added to the mixer,
using the following formula:
9.4 Interpretation of Torque Rheometer Curve (Fig. 1):
9.4.1 Fusion Torque—The point of maximum torque.
sample size 5 @~V 2 D! 365%# 3specific gravity (1)
9.4.2 Fusion Time—The time from the point of loading to
where:
the point of maximum torque.
V = volume of mixer bowl without rotors, and
9.4.3 Melt Torque—The fusion where the torque curve is
D = volume displacement or rotors.
relatively flat.
NOTE4—Thecorrectsamplesizeforthemixeriswhenthefusioncurve
9.5 Report—Report the following information:
will duplicate itself. As the mixer wears, it will be necessary to increase
the sample size to reproduce a fusion curve equivalent to previous curves. 9.5.1 The fusion torque to the nearest 100 m·g.
D2538 − 02 (2010)
9.5.1.1 Report to the nearest 25 m·g when usinga0to 1000 11.3.3 Mount the samples in a sequential time order.
scale. 11.3.4 Continue sampling until the desired color change has
9.5.2 The fusion time to the nearest ⁄2 min. been observed.
9.5.3 The melt torque to the nearest 100 m·g.
NOTE 7—Depleting the sample from the bowl can affect the amount of
9.5.3.1 Report to the nearest 25 m·g when usinga0to 1000
working the compound receives. Select a time sequence that does not
scale.
remove more than half the sample.
11.3.5 Stop the mixer and open the bowl. Clean the com-
NOTE 6—If the melt torque is not steady, approximate the value and
note whether the torque is increasing or decreasing.
pound from the bowl and blades, using the brass knife or wool,
or both.
9.5.4 Temperature of test, rotor revolutions per minute, and
11.3.6 Reassemble the mixing bowl and repeat 11.3.1 –
sample size used.
11.3.5 for additional tests. Confirm that the bowl has reached
10. Thermal Stability Test Method
the test temperature before starting.
10.1 Prepare the test compound in accordance with 9.1.
11.4 Report—Report the following information:
11.4.1 The time to equivalent color change and
10.2 Prepare the test equipment in accordance with 9.2.
11.4.2 The temperature of test, rotor revolutions per minute,
10.3 Procedure:
and the sample size used.
10.3.1 Weigh a sample of the test compound in accordance
11.5 Alternative Procedure:
with 9.3.1. With the mixer running, position the quick-loading
11.5.1 Weigh a sample of the test compound in accordance
chute on the roller-head mixer and pour in the sample com-
with 9.3.1. With the mixer running, position the quick-loading
pound. Place the ram into the chute and add the weight. When
chute on the roller-head mixer and pour in the sample com-
thetorquecurveindicatesfusion,removetheloadingchuteand
pound. Place the ram into the chute and add the weight. When
weight.
thetorquecurveindicatesfusion,removetheloadingchuteand
10.3.2 Continue running until there is a sudden rise in the
the weight.
torque curve, indicating decomposition of the PVC compound.
11.5.2 Using the point of maximum torque (fusion torque)
10.3.3 Stop the mixer and open the bowl. Clean the com-
as zero time, run the mixer until the compound starts to
pound from the bowl and blades using the brass knife or wool,
discolor. Stop the mixer, remove the contents, and press into a
or both.
plaque.
10.3.4 Reassemble the mixing bowl and repeat 10.3.1 –
11.5.3 Clean the bowl and blades and reassemble the mixer.
10.3.3 for additional tests. Confirm that the bowl has reached
11.5.4 Run additional tests, stopping at the same point in
the test temperature before starting.
time as 11.5.2.
10.4 Interpretation of Torque Rheometer Curve (Fig. 1):
11.5.5 Measure the color of the plaque in a Hunter Colo-
10.4.1 Compound Heat Stability—The time from the point
rimeter (or equivalent).
of maximum torque (fusion torque) to the point of sudden
11.6 Report—Report the following information:
torque increase.
11.6.1 The color number measured on the pressed plaque
10.5 Report—Report the following information:
and
10.5.1 The compound heat stability to the nearest ⁄2 min,
11.6.2 The temperature of the test, rotor revolutions per
and
minute, the sample size, and the time as determined in 11.5.2.
10.5.2 The temperature of test, rotor revolutions per minute,
and the sample size used.
12. Shear Stability Test Method
11. Color-Hold Stability Test Method 12.1 Prepare the test compound i
...
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